add getIsScissorEnable() and getScissorRect() for CCEGLViewProtocal
change method name from getIsScissorEnable() to isScissorEnable()
Fix the display bug when a scrollView nested in another scrollView
change a method name

change method name from isScissorEnable() to isScissorEnabled() in
class CCEGLViewProtocal
change comment type
Merge pull request #2279 from sjchao/master

fixed #2030: Fixing a display bug when a scrollView nested in another scrollView. The parent's scissor rect need to be considered, when setting the scissor rect in the subScrollView.