Update CCDirectorCaller.mm

First destroy CCDirector instance with  cocos2d::CCDirector::sharedDirector()->end() 

Then create new CCDirector instance with
cocos2d::CCApplication::sharedApplication()->run();

APP will crash at 
CCApplication::setAnimationInterval

[[CCDirectorCaller sharedDirectorCaller] setAnimationInterval: interval ];
Merge pull request #2247 from hailongiPhone/master

release && set nil
Fix linux compilation of CCTexturePVR.cpp

On linux (and possibly other platforms)
GL_COMPRESSED_RGB_PVRTC_2BPPV1_IMG is simply not defined since we don't
include GLES/gl2ext.h.
Merge pull request #2243 from sbc100/fix_linux_build

Fix linux compilation of CCTexturePVR.cpp