Refactor build (#493)

* Add lint/format checks to build
* Make travis get full repo to get tags
* Run packr2 once in cross-compile
* Fix quotes in package.json
* Fix linting issues
* Formatting
* Fix vet issue
* Fix go lint issues
* Show start of each platform compilation
* Add validate target
* Set gitattributes for go fmt and mod vendor
* Fix tag name
* Add fmt-ui target

pkg/ffmpeg/encoder.go

@@ -18,8 +18,8 @@ type Encoder struct {
 }
 
 var (
-	runningEncoders      map[string][]*os.Process = make(map[string][]*os.Process)
-	runningEncodersMutex                          = sync.RWMutex{}
+	runningEncoders      = make(map[string][]*os.Process)
+	runningEncodersMutex = sync.RWMutex{}
 )
 
 func NewEncoder(ffmpegPath string) Encoder {