Added define for OUYA to the CFlags to let the code of cocos2d-x know it is build for OUYA
Added include directives for the platform relevant files in cocos2d.h
Fixed the setting of CC_PLATFORM_TARGET. CC_PLATFORM_TARGET = CC_PLATFORM_ANDROID was set before anyway, because the NDK defines ANDROID. This deterred OUYA from being set, because CC_PLATFORM_TARGET was already set to a platform.
Added the CC_PLATFORM_OUYA to all code which was specific for Android and not inside plaform/ouya.