Add more warning flags, fix a few new warnings

src/ucore_murmurhash.c

@@ -20,7 +20,7 @@ uc_murmurmash2(const void *key, int len, uint32_t seed )
 
     while(len >= 4)
     {
-        uint32_t k = *(uint32_t *)data;
+        uint32_t k = *(const uint32_t *)data;
 
         k *= m; 
         k ^= k >> r;