Upgrade rugged to latest version

Changes:

   * Upgraded rugged, fixed API calls
   * Fixed deprecated call to File.exists?
   * Removed deprecated rspec config option
Merge branch 'master' of github.com:thegarage/thegarage-gitx into rugged-upgrade

Conflicts:
	spec/spec_helper.rb
	thegarage-gitx.gemspec
Bump version number, change Travis ruby version to 2.1.2
Change to travis config to fix test failures in CI.
Merge pull request #9 from thegarage/rugged-upgrade

Upgrade `rugged`, Bump Version Number.