add init function

hashtable.c

@@ -23,6 +23,10 @@ entry_hash_t key_hash(entry_key_t key) {
 	return strhash_str(key) + 1; // make hash always nonzero
 }
 
+void hashtable_init(struct hashtable * table) {
+	memset(table, 0, sizeof(table));
+}
+
 hashtable_iterator_t hashtable_end(struct hashtable * table) {
 	return table->data + table->len;
 }