Switch to npm installed casperjs for testing.
Remove unused .gitignore files.
Remove CasperJS from GeoExt repository.
Tag CasperJS version for testing.
Update Readme describing how to run headless tests locally.
Update .gitignore to make sure no node modules are accidentally committed.
Merge pull request #285 from bentrm/travis

Remove CasperJS from the GeoExt repository only installing it via NPM if needed.