Merge branch 'development' into v2-prototype

* development: (29 commits)
  Do not remove artifacts when running `clean`
  fix style errors
  Fix circular dependency
  Add my profile image to images
  Add myself to about page
  Add dogfood configs to website
  Revert to lerna:run lint
  Do lint sequentially
  Exclude monorepo-scripts from tslint as test
  Fix prettier
  Add hover state to top tokens
  Change to weekly txn volume
  Change minimum Node version to 6.12
  Document Node.js version requirement and add it to package.json
  Apply prettier to some files which were not formatted correctly
  Fix TSLint issues
  Fix TSLint issues
  Update ethereeumjs-testrpc to ganache-cli
  Fix infinite loop
  Add changelog entries for packages where executable binary exporting fixed
  ...

# Conflicts:
#	packages/contracts/package.json
#	packages/contracts/util/formatters.ts
#	packages/contracts/util/signed_order_utils.ts
#	packages/migrations/package.json
#	yarn.lock

4 files changed, 14 insertions, 19 deletions

diff --git a/packages/utils/README.md b/packages/utils/README.md
index 914404937..c637c9af5 100644
--- a/packages/utils/README.md
+++ b/packages/utils/README.md
@@ -44,28 +44,16 @@ yarn install
 
 ### Build
 
-If this is your **first** time building this package, you must first build **all** packages within the monorepo. This is because packages that depend on other packages located inside this monorepo are symlinked when run from **within** the monorepo. This allows you to make changes across multiple packages without first publishing dependent packages to NPM. To build all packages, run the following from the monorepo root directory:
+To build this package and all other monorepo packages that it depends on, run the following from the monorepo root directory:
 
 ```bash
-yarn lerna:rebuild
+PKG=@0xproject/utils yarn build
 ```
 
 Or continuously rebuild on change:
 
 ```bash
-yarn dev
-```
-
-You can also build this specific package by running the following from within its directory:
-
-```bash
-yarn build
-```
-
-or continuously rebuild on change:
-
-```bash
-yarn build:watch
+PKG=@0xproject/utils yarn watch
 ```
 
 ### Clean
diff --git a/packages/utils/package.json b/packages/utils/package.json
index 0924aefc3..d39077148 100644
--- a/packages/utils/package.json
+++ b/packages/utils/package.json
@@ -1,11 +1,14 @@
 {
     "name": "@0xproject/utils",
     "version": "0.6.1",
+    "engines": {
+        "node" : ">=6.12"
+    },
     "description": "0x TS utils",
     "main": "lib/index.js",
     "types": "lib/index.d.ts",
     "scripts": {
-        "build:watch": "tsc -w",
+        "watch": "tsc -w",
         "build": "tsc && copyfiles -u 2 './lib/monorepo_scripts/**/*' ./scripts",
         "clean": "shx rm -rf lib scripts",
         "lint": "tslint --project .",
diff --git a/packages/utils/src/abi_decoder.ts b/packages/utils/src/abi_decoder.ts
index 150f74a15..d329f917a 100644
--- a/packages/utils/src/abi_decoder.ts
+++ b/packages/utils/src/abi_decoder.ts
@@ -17,7 +17,7 @@ import { BigNumber } from './configured_bignumber';
 export class AbiDecoder {
     private _savedABIs: AbiDefinition[] = [];
     private _methodIds: { [signatureHash: string]: EventAbi } = {};
-    private static _padZeros(address: string) {
+    private static _padZeros(address: string): string {
         let formatted = address;
         if (_.startsWith(formatted, '0x')) {
             formatted = formatted.slice(2);
diff --git a/packages/utils/src/interval_utils.ts b/packages/utils/src/interval_utils.ts
index ebecc7015..6984bf42d 100644
--- a/packages/utils/src/interval_utils.ts
+++ b/packages/utils/src/interval_utils.ts
@@ -1,7 +1,11 @@
 import * as _ from 'lodash';
 
 export const intervalUtils = {
-    setAsyncExcludingInterval(fn: () => Promise<void>, intervalMs: number, onError: (err: Error) => void) {
+    setAsyncExcludingInterval(
+        fn: () => Promise<void>,
+        intervalMs: number,
+        onError: (err: Error) => void,
+    ): NodeJS.Timer {
         let locked = false;
         const intervalId = setInterval(async () => {
             if (locked) {
@@ -21,7 +25,7 @@ export const intervalUtils = {
     clearAsyncExcludingInterval(intervalId: NodeJS.Timer): void {
         clearInterval(intervalId);
     },
-    setInterval(fn: () => void, intervalMs: number, onError: (err: Error) => void) {
+    setInterval(fn: () => void, intervalMs: number, onError: (err: Error) => void): NodeJS.Timer {
         const intervalId = setInterval(() => {
             try {
                 fn();