HTTP Basic Authentication is basically a one-liner and it's a waste to depend on a Gem for this functionality. Another reason not to depend on HTTPAuth is that it's no longer maintained.
Because require hashes based on the string, not the expanded path of the file, it's important that we require the version file the same way that it will be required elsewhere to avoid constant warnings.
Use `Object#respond_to?` to determine which MultiJson API to use.
Add client credentials grant type
…th multi_json 1.0 and greater