Tweak gemfiles and tavis.yml
Stick to RSpec 2.x for now...
How could the specs be run without rspec gem being bundled??
Use the stable rspec release (but still not 3.0...)
Update docs badge in README

Update the URL of the docs badge to include it from inch-ci.org instead of inch-pages.github.io (the former being the successor of the Inch Pages project).
Merge pull request #563 from rrrene/patch-2

Update docs badge in README [ci skip]