Cleanups in JNI related code

Removed the malloc version in binary dictionary support -- this has not
really been tested well so far, and the mmap version has been working pretty
well after all.

Several cosmetic fixes etc.

Change-Id: Iad0da58b300b769fb5946a3e73fc96f56215980e
diff --git a/native/jni/jni_common.h b/native/jni/jni_common.h
index f960b05..ef72a7c 100644
--- a/native/jni/jni_common.h
+++ b/native/jni/jni_common.h
@@ -20,7 +20,7 @@
 #include "jni.h"
 
 namespace latinime {
-int registerNativeMethods(JNIEnv *env, const char *className, JNINativeMethod *methods,
-        int numMethods);
+int registerNativeMethods(JNIEnv *env, const char *const className, const JNINativeMethod *methods,
+        const int numMethods);
 } // namespace latinime
 #endif // LATINIME_JNI_COMMON_H