原仓库地址：https://github.com/romaonthego/RESideMenu
原作者好像已经不维护了，添加了一些接口，可以简单设置成QQ的风格。
RESideMenu.m所有改动处都有//M标记。
增加的接口：
@property (strong, readwrite, nonatomic) IBInspectable UIColor *contentMaskColor;
@property (assign, readwrite, nonatomic) IBInspectable CGFloat contentMaskViewAlpha;
@property (assign, readwrite, nonatomic) IBInspectable BOOL maskViewEnabled;
@property (nonatomic, assign) CGFloat panGesturePointX;