Version 1.0.3

English:
1.Fix one bug of error progressX variable reference
2.add setDragOffset(int width) method
3.add extra width for MenuLayout to improve rebound effect in Api < 21

Version 1.0.2

1.Fix a fatal Bug:when dragging down to the bottom screen(Y axis coordinates greater than the view height),the menuview will become blank
2.Provide onProgressUpdate callback in MenuListener

Init Version

Implements SpringMenu