General modernization

Hello! This is a major PR that hopefully cleans up a lot of things.

* Remove Gemfile.lock: best practice for a gem is that it should not include a Gemfile.lock. It's unnecessary. Any dependencies should be specified in the .gemspec. See http://stackoverflow.com/questions/4151495/should-gemfile-lock-be-included-in-gitignore

* Remove jeweler - it's old & you can simply use gem. See http://yehudakatz.com/2010/04/02/using-gemspecs-as-intended/

* Updated .gemspec & Rakefile to work without jeweler

* Remove app directory. There should not be a rails app included in this library. It could be put into a separate project as an example.

* I took the liberty of bumping the version & also bumping the ruby version for travis.

Tests pass & I built a local gem that works in our rails app.

Thanks!