core: initial commit for logger (#228)

* Replace "log.*" with logger.
* Add simple logger to log with log package.
* Add debug logs to all calls to these interfaces:
   - core.Application
   - core.Governance
   - core.Network
* Add Stringer to these types:
   - types.DKGComplaint
   - types.AgreementResult
   - types.DKGMasterPublicKey
   - types.DKGFinalize

1 files changed, 8 insertions, 1 deletions

diff --git a/core/types/position.go b/core/types/position.go
index 4e254ba..51de405 100644
--- a/core/types/position.go
+++ b/core/types/position.go
@@ -17,7 +17,10 @@
 
 package types
 
-import "errors"
+import (
+	"errors"
+	"fmt"
+)
 
 // ErrComparePositionOnDifferentChains raised when attempting to
 // compare two positions with different chain ID.
@@ -31,6 +34,10 @@ type Position struct {
 	Height  uint64 `json:"height"`
 }
 
+func (pos *Position) String() string {
+	return fmt.Sprintf("pos[%d:%d:%d]", pos.ChainID, pos.Round, pos.Height)
+}
+
 // Equal checks if two positions are equal, it panics when their chainIDs
 // are different.
 func (pos *Position) Equal(other *Position) bool {