update to fix compatibility with Typhoeus >= 0.5.0

should address https://github.com/oauth-xx/oauth-ruby/issues/68
update documentation to reflect new Typhoeus
Merge pull request #1 from afar/master

Update Readme
Merged #83 pull request, fixed merge conflicts.
Do not duplicate gems in Gemfile, gemspec is enough.
Fixed mocha integration
Typhoeus supposes that request method is GET by default when it's not specified in options. We have to handle this in request proxy.
Parameters set with options are same as specified via query string.
Anyway we normalize them so it doesn't matter what we have, string or array with one string element.
Merge pull request #94 from raeno/83-merge-typhoeus-compatibility

Fixed typhoeus compatibility. Cleaned gemfile. Made tests green.