Add the base sample code for ads
Solve the bug in ant build.
Add ads protocol.
Add plugin admob for android platform.
Add sample code HelloAds for android platform
Merge branch 'master' of https://github.com/cocos2d/cocos2d-x
fixed #2073: fix memory leak in CCUserDefault
Merge pull request #2420 from minggo/2073-userdefault_memory_leak_

fixed #2073: fix memory leak in CCUserDefault
Merge pull request #2419 from natural-law/master

Add protocol Ads & plugin Admob
Update the iOS projects in plugin, and remove the win32 projects.
Merge pull request #2421 from natural-law/master

issue #1723 : Update the iOS projects in plugin, and remove the win32 projects.
Adding popSceneBack() function to CCDirector

This function deletes the running scene and returns the actual scene
back to the caller. This way, we can simply use it to perform a
transition animation, like this:

    CCDirector::sharedDirector()->replaceScene(
            CCTransitionSlideInL::create(0.5,
            CCDirector::sharedDirector()->popSceneBack()));

Signed-off-by: Rodrigo Goncalves de Oliveira <rodrigo.goncalves@openbossa.org>