Merge PR #1429: tools: Add ineffassign linter

* tools: Add ineffassign linter

This errors on assignments that don't actually do anything. i.e.

x, err := myFunc(1)
y, err = myFunc(2)

This will call out that the first function's call error was never
used.

* Fix makefile, add misspell to makefile

examples/democoin/app/app_test.go

@@ -43,6 +43,7 @@ func TestGenesis(t *testing.T) {
 		},
 	}
 	stateBytes, err := json.MarshalIndent(genesisState, "", "\t")
+	require.Nil(t, err)
 
 	vals := []abci.Validator{}
 	bapp.InitChain(abci.RequestInitChain{Validators: vals, AppStateBytes: stateBytes})

examples/democoin/cmd/democoind/main.go

@@ -34,6 +34,9 @@ func CoolAppGenState(cdc *wire.Codec, appGenTxs []json.RawMessage) (appState jso
         "trend": "ice-cold"
       }`)
 	appState, err = server.AppendJSON(cdc, appState, key, value)
+	if err != nil {
+		return
+	}
 	key = "pow"
 	value = json.RawMessage(`{
         "difficulty": 1,

examples/democoin/x/simplestake/keeper_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 
 	abci "github.com/tendermint/abci/types"
 	crypto "github.com/tendermint/go-crypto"
@@ -79,6 +80,7 @@ func TestBonding(t *testing.T) {
 	assert.Nil(t, err)
 
 	power, err := stakeKeeper.bondWithoutCoins(ctx, addr, pubKey, sdk.NewCoin("steak", 10))
+	require.Nil(t, err)
 	assert.Equal(t, int64(20), power)
 
 	pk, _, err := stakeKeeper.unbondWithoutCoins(ctx, addr)