core: Adds input placeholder in the textfields
Facebook: Split Controller into Traits.

This should make everything a bit more organized.
Facebook: Add get_app_access_token() webservice.
General: Switch from error enums to the Lunr error constants.
Facebook: Add get_page_data() webservice.
Facebook: Fix small issues in the Authentication Trait.
Core: Make output values accessible by css selectors.

Cleanup display of output values a bit in the process.
General: Make Virus cli invokeable.
Facebook: Use correct input parameters for get_*_url methods.
tests: Add behavior test infrastructure.
buildsystem: Store casperjs results in .xml instead of .log.