Merge pull request #86 from kl/master

Improved file name checking
Start using shellescape library
Remove mechanize, update gem requirements.
Add caching for bundler and apt on travis
Use tmpdir for integration tests and fix other filename related things in audio extraction
Allow Jruby and Rubinius to fail :-/
Add json for rubinius testing
Remove the rubinius json fix again.
Bump version.
Speed up travis by only calling 'apt-get install' once