preserving changes
merged
added monkey patch to Object for to_json and made JSON::ParseError not warn if already defined
added monkey patch to Object for to_json and made JSON::ParseError not warn if already defined
Improve $LOADED_FEATURES append pattern

```start_with?('json')``` is not correct implementation.
For example, this prevents ```json_spec``` gem from being loaded.
Regular expression which checks if there is a file or folder starting
with json works better.