Makefile and source code structure update for LatinIME AOSP build

native/jni/Android.mk

native/jni/src/dictionary.cpp

native/jni/src/dictionary.h

native/jni/src/gesture/gesture_decoder.h

native/jni/src/gesture/impl/gesture_decoder_impl.cpp

native/jni/src/gesture/impl/gesture_decoder_impl.h

native/jni/src/gesture/impl/incremental_decoder_impl.cpp

native/jni/src/gesture/impl/incremental_decoder_impl.h

native/jni/src/gesture/impl/token_beam_impl.cpp

native/jni/src/gesture/impl/token_beam_impl.h

native/jni/src/gesture/impl/token_impl.cpp

native/jni/src/gesture/impl/token_impl.h

native/jni/src/gesture/incremental_decoder.h

native/jni/src/gesture/incremental_decoder_interface.cpp

native/jni/src/gesture/incremental_decoder_interface.h