Remove and ignore gemfiles

These are automatically generated by `appraisal`/`rake`. See also:
https://github.com/thoughtbot/shoulda/pull/232.
Sort .gitignore
Removed gemfiles from .travis.yml

We already use Appraisal for regression tests. Combining that with
Travis-CI's gemfile management blows up.
Merge pull request #235 from rmm5t/fix-travis-builds

Fix Travis-CI build
Added gem version badge to the readme

[ci skip]
Bumped version to 3.4.0

closes #236
Added ruby 1.9.3 to the travis build
Allow travis failures for ruby 1.8.7
Added ruby 2.0 to the build matrix
Consolidated readme intro
Updated generated gemfiles in prep for supporting shoulda-matchers 2.x
Relaxed dependencies to allow shoulda-matchers 2.x
Bumped version to 3.5.0
Merge branch 'ignore_gemfiles' of https://github.com/sferik/shoulda into sferik-ignore_gemfiles

# By Erik Michaels-Ober
# Via Erik Michaels-Ober
* 'ignore_gemfiles' of https://github.com/sferik/shoulda:
  Sort .gitignore
  Remove and ignore gemfiles

Conflicts:
	gemfiles/3.0.gemfile
	gemfiles/3.0.gemfile.lock
	gemfiles/3.1.gemfile
	gemfiles/3.1.gemfile.lock
	gemfiles/3.2.gemfile
	gemfiles/3.2.gemfile.lock