fix shapeshifter gomobile builds for Android...

... by renaming ShapeShifter struct to Shapeshifter

This MR fixes building shapeshifter go lib. Even though this lib is going to be replaced, it can be optionally used instead of obfsvpn in Bitmask Android and its custom branded versions.

Not sure if Bitmask Destop is still using shapeshifter at all. we then may to adapt a little bit of code there as well.

shapeshifter.go

@@ -37,17 +37,17 @@ type Logger interface {
 	Log(msg string)
 }
 
-type ShapeShifter struct {
+type Shapeshifter struct {
 	Cert      string
 	IatMode   int
 	Target    string // remote ip:port obfs4 server
-	SocksAddr string // -proxylistenaddr in shapeshifter-dispatcher
+	SocksAddr string // -proxylistenaddr in Shapeshifter-dispatcher
 	Logger    Logger
 	ln        net.Listener
 	errChan   chan error
 }
 
-func (ss *ShapeShifter) Open() error {
+func (ss *Shapeshifter) Open() error {
 	err := ss.checkOptions()
 	if err != nil {
 		return err
@@ -62,7 +62,7 @@ func (ss *ShapeShifter) Open() error {
 	return nil
 }
 
-func (ss *ShapeShifter) Close() error {
+func (ss *Shapeshifter) Close() error {
 	var err error
 	if ss.ln != nil {
 		err = ss.ln.Close()
@@ -73,14 +73,14 @@ func (ss *ShapeShifter) Close() error {
 	return err
 }
 
-func (ss *ShapeShifter) GetErrorChannel() chan error {
+func (ss *Shapeshifter) GetErrorChannel() chan error {
 	if ss.errChan == nil {
 		ss.errChan = make(chan error, 2)
 	}
 	return ss.errChan
 }
 
-func (ss ShapeShifter) clientAcceptLoop() error {
+func (ss Shapeshifter) clientAcceptLoop() error {
 	for {
 		conn, err := ss.ln.Accept()
 		if err != nil {
@@ -94,7 +94,7 @@ func (ss ShapeShifter) clientAcceptLoop() error {
 	}
 }
 
-func (ss ShapeShifter) clientHandler(conn net.Conn) {
+func (ss Shapeshifter) clientHandler(conn net.Conn) {
 	defer conn.Close()
 
 	dialer := proxy.Direct
@@ -177,7 +177,7 @@ func copyLoop(a net.Conn, b net.Conn) error {
 	return nil
 }
 
-func (ss *ShapeShifter) checkOptions() error {
+func (ss *Shapeshifter) checkOptions() error {
 	if ss.SocksAddr == "" {
 		ss.SocksAddr = "127.0.0.1:0"
 	}
@@ -185,7 +185,7 @@ func (ss *ShapeShifter) checkOptions() error {
 	return err
 }
 
-func (ss *ShapeShifter) sendError(format string, a ...interface{}) {
+func (ss *Shapeshifter) sendError(format string, a ...interface{}) {
 	if ss.Logger != nil {
 		ss.Logger.Log(fmt.Sprintf(format, a...))
 		return