Godeps, vendor: convert dependency management to trash (#3198)

This commit converts the dependency management from Godeps to the vendor
folder, also switching the tool from godep to trash. Since the upstream tool
lacks a few features proposed via a few PRs, until those PRs are merged in
(if), use github.com/karalabe/trash.

You can update dependencies via trash --update.

All dependencies have been updated to their latest version.

Parts of the build system are reworked to drop old notions of Godeps and
invocation of the go vet command so that it doesn't run against the vendor
folder, as that will just blow up during vetting.

The conversion drops OpenCL (and hence GPU mining support) from ethash and our
codebase. The short reasoning is that there's noone to maintain and having
opencl libs in our deps messes up builds as go install ./... tries to build
them, failing with unsatisfied link errors for the C OpenCL deps.

golang.org/x/net/context is not vendored in. We expect it to be fetched by the
user (i.e. using go get). To keep ci.go builds reproducible the package is
"vendored" in build/_vendor.

1 files changed, 245 insertions, 0 deletions

diff --git a/vendor/gopkg.in/fatih/set.v0/README.md b/vendor/gopkg.in/fatih/set.v0/README.md
new file mode 100644
index 000000000..23afdd98d
--- /dev/null
+++ b/vendor/gopkg.in/fatih/set.v0/README.md
@@ -0,0 +1,245 @@
+# Set [![GoDoc](http://img.shields.io/badge/go-documentation-blue.svg?style=flat-square)](https://godoc.org/gopkg.in/fatih/set.v0) [![Build Status](http://img.shields.io/travis/fatih/set.svg?style=flat-square)](https://travis-ci.org/fatih/set)
+
+Set is a basic and simple, hash-based, **Set** data structure implementation
+in Go (Golang).
+
+Set provides both threadsafe and non-threadsafe implementations of a generic
+set data structure. The thread safety encompasses all operations on one set.
+Operations on multiple sets are consistent in that the elements of each set
+used was valid at exactly one point in time between the start and the end of
+the operation. Because it's thread safe, you can use it concurrently with your
+goroutines.
+
+For usage see examples below or click on the godoc badge.
+
+## Install and Usage
+
+Install the package with:
+
+```bash
+go get gopkg.in/fatih/set.v0
+```
+
+Import it with:
+
+```go
+import "gopkg.in/fatih/set.v0"
+```
+
+and use `set` as the package name inside the code.
+
+## Examples
+
+#### Initialization of a new Set
+
+```go
+
+// create a set with zero items
+s := set.New()
+s := set.NewNonTS() // non thread-safe version
+
+// ... or with some initial values
+s := set.New("istanbul", "frankfurt", 30.123, "san francisco", 1234)
+s := set.NewNonTS("kenya", "ethiopia", "sumatra")
+
+```
+
+#### Basic Operations
+
+```go
+// add items
+s.Add("istanbul")
+s.Add("istanbul") // nothing happens if you add duplicate item
+
+// add multiple items
+s.Add("ankara", "san francisco", 3.14)
+
+// remove item
+s.Remove("frankfurt")
+s.Remove("frankfurt") // nothing happes if you remove a nonexisting item
+
+// remove multiple items
+s.Remove("barcelona", 3.14, "ankara")
+
+// removes an arbitary item and return it
+item := s.Pop()
+
+// create a new copy
+other := s.Copy()
+
+// remove all items
+s.Clear()
+
+// number of items in the set
+len := s.Size()
+
+// return a list of items
+items := s.List()
+
+// string representation of set
+fmt.Printf("set is %s", s.String())
+
+```
+
+#### Check Operations
+
+```go
+// check for set emptiness, returns true if set is empty
+s.IsEmpty()
+
+// check for a single item exist
+s.Has("istanbul")
+
+// ... or for multiple items. This will return true if all of the items exist.
+s.Has("istanbul", "san francisco", 3.14)
+
+// create two sets for the following checks...
+s := s.New("1", "2", "3", "4", "5")
+t := s.New("1", "2", "3")
+
+
+// check if they are the same
+if !s.IsEqual(t) {
+    fmt.Println("s is not equal to t")
+}
+
+// if s contains all elements of t
+if s.IsSubset(t) {
+	fmt.Println("t is a subset of s")
+}
+
+// ... or if s is a superset of t
+if t.IsSuperset(s) {
+	fmt.Println("s is a superset of t")
+}
+
+
+```
+
+#### Set Operations
+
+
+```go
+// let us initialize two sets with some values
+a := set.New("ankara", "berlin", "san francisco")
+b := set.New("frankfurt", "berlin")
+
+// creates a new set with the items in a and b combined.
+// [frankfurt, berlin, ankara, san francisco]
+c := set.Union(a, b)
+
+// contains items which is in both a and b
+// [berlin]
+c := set.Intersection(a, b)
+
+// contains items which are in a but not in b
+// [ankara, san francisco]
+c := set.Difference(a, b)
+
+// contains items which are in one of either, but not in both.
+// [frankfurt, ankara, san francisco]
+c := set.SymmetricDifference(a, b)
+
+```
+
+```go
+// like Union but saves the result back into a.
+a.Merge(b)
+
+// removes the set items which are in b from a and saves the result back into a.
+a.Separate(b)
+
+```
+
+#### Multiple Set Operations
+
+```go
+a := set.New("1", "3", "4", "5")
+b := set.New("2", "3", "4", "5")
+c := set.New("4", "5", "6", "7")
+
+// creates a new set with items in a, b and c
+// [1 2 3 4 5 6 7]
+u := set.Union(a, b, c)
+
+// creates a new set with items in a but not in b and c
+// [1]
+u := set.Difference(a, b, c)
+
+// creates a new set with items that are common to a, b and c
+// [5]
+u := set.Intersection(a, b, c)
+```
+
+#### Helper methods
+
+The Slice functions below are a convenient way to extract or convert your Set data
+into basic data types.
+
+
+```go
+// create a set of mixed types
+s := set.New("ankara", "5", "8", "san francisco", 13, 21)
+
+
+// convert s into a slice of strings (type is []string)
+// [ankara 5 8 san francisco]
+t := set.StringSlice(s)
+
+
+// u contains a slice of ints (type is []int)
+// [13, 21]
+u := set.IntSlice(s)
+
+```
+
+#### Concurrent safe usage
+
+Below is an example of a concurrent way that uses set. We call ten functions
+concurrently and wait until they are finished. It basically creates a new
+string for each goroutine and adds it to our set.
+
+```go
+package main
+
+import (
+	"fmt"
+	"github.com/fatih/set"
+	"strconv"
+	"sync"
+)
+
+func main() {
+	var wg sync.WaitGroup // this is just for waiting until all goroutines finish
+
+	// Initialize our thread safe Set
+	s := set.New()
+
+	// Add items concurrently (item1, item2, and so on)
+	for i := 0; i < 10; i++ {
+		wg.Add(1)
+		go func(i int) {
+			item := "item" + strconv.Itoa(i)
+			fmt.Println("adding", item)
+			s.Add(item)
+			wg.Done()
+		}(i)
+	}
+
+	// Wait until all concurrent calls finished and print our set
+	wg.Wait()
+	fmt.Println(s)
+}
+```
+
+## Credits
+
+ * [Fatih Arslan](https://github.com/fatih)
+ * [Arne Hormann](https://github.com/arnehormann)
+ * [Sam Boyer](https://github.com/sdboyer)
+ * [Ralph Loizzo](https://github.com/friartech)
+
+## License
+
+The MIT License (MIT) - see LICENSE.md for more details
+