Trying out trusty build on travis.

Should fix https://github.com/timvideos/gst-switch/issues/57
Try not running via bash.
Small refactor of the .travis files.
Fixing missing sudo.
Use the .py script.
Merge pull request #85 from mithro/travis-fix

Make gst-switch build with Ubuntu 14.04 (trusty tahr) on Travis-CI