fix ndk build problems on eclipse and unsatisfied link error for both sample projects

The sample projects doesn't build the ndk files in eclipse, so I:
1. configure the build chain (.project and .cproject)
2. fix the unsatisfied link error: for the Cocos2dxActivity to load the lib, the meta-data "android.app.lib_name" need to be placed directly under <application> tag in AndroidManifest.xml, not <activity> tag