Add travis-ci config
Gemfile.lock should not go in a gem's repo

Ref: http://yehudakatz.com/2010/12/16/clarifying-the-roles-of-the-gemspec-and-gemfile/

Also added default `bundler gem` .gitignore.
Pickup bundler env with the `rake` command  
Default to readable spec output in travis
Merge branch 'travis-ci'

Conflicts:
	Gemfile.lock