Update third party dependencies
Convert back to LESS

Fits workflow better, no need to use sass-bootstrap, no Ruby required
for building.
PhantomJSDriver
Build on travis-ci
Rename informant submodule to core

This should help avoid confusion when referring to the 'informant'
folder (e.g. see README.md).
Switch back to Firefox for WebDriver tests

Seeing sporadic failures when using PhantomJS driver, see
https://github.com/detro/ghostdriver/issues/140.
Update to use new shaded artifact name