Android: Implement dw_window_new(), dw_box_new() and dw_box_pack(). Initialize JNI when creating new threads. Include jni.h from dw.h so we can type HWND as jobject. Remove our own resize code, we are going to try to use LinearLayout.

# Set these here to change the version for all platforms
DW_MAJOR_VERSION=3
DW_MINOR_VERSION=2