Replace assert() with ASSERT() & use -funwind-tables for debug builds

native/jni/Android.mk

native/jni/jni_common.cpp

native/jni/src/correction.cpp

native/jni/src/correction.h

native/jni/src/proximity_info.cpp

native/jni/src/unigram_dictionary.cpp

native/jni/src/words_priority_queue_pool.h