Adds fuzzyHash operator

The fuzzyHash operator can be used to match files. In conjuntcion
with FILES_TMP_CONTENT collection it can scan uploaded files and
try to match it with a pre caculated list of know malicious content,
more details on how it works can be found on ssdeep website:
http://ssdeep.sourceforge.net/

apache2/re.h

@@ -409,4 +409,9 @@ struct msre_cache_rec {
     apr_size_t               val_len;
 };
 
+struct fuzzy_hash_param_data {
+    const char *file;
+    int threshold;
+};
+
 #endif