Fix parameters of native functions and refactor Dictionary

- created bigram/unigram dictionary classes

Change-Id: I233a28ed8d611870db3f4cf8f25fc45b5d41529b
diff --git a/native/Android.mk b/native/Android.mk
index 97051c9..bbbff1e 100644
--- a/native/Android.mk
+++ b/native/Android.mk
@@ -4,9 +4,11 @@
 LOCAL_C_INCLUDES += $(LOCAL_PATH)/src
 
 LOCAL_SRC_FILES := \
-	jni/com_android_inputmethod_latin_BinaryDictionary.cpp \
-	src/dictionary.cpp \
-	src/char_utils.cpp
+    jni/com_android_inputmethod_latin_BinaryDictionary.cpp \
+    src/bigram_dictionary.cpp \
+    src/char_utils.cpp \
+    src/dictionary.cpp \
+    src/unigram_dictionary.cpp
 
 #FLAG_DBG := true