util cleanup (#1474)

* removed old json-tests

* simplify folds in triehash.rs

* removed unused json_aid

* removed unused squeeze.rs

* json branching tests for trie

* loading trie consensus tests

ethcore/src/json_tests/mod.rs

@@ -23,3 +23,4 @@ mod state;
 mod chain;
 mod homestead_state;
 mod homestead_chain;
+mod trie;