Merge pull request #611 from chrox/master

use android config interface to detect device keyboard and screen dpi
Android: use FFI-based dlopen() and JNI interfacing
Merge pull request #613 from hwhw/master

Android: use FFI-based dlopen() and JNI interfacing
fix FC in Android 2.3 when calling util.realpath
fix blank screen on Android 2.3
Now blitbuffer is initialized with android.screen field
which is possible to grab before native activity window is inited.