feature(group filter): add display condition for filters

Filters are only display if context is a group
Fix (imports): update zcml import according to ptheme.jqm
fix(audio): Fix display of the tile

Make the tile use same view api as the audio_view
feature(event): start to implement event_view

Use the event_view table and adapt it to our content type. this is a
work in progress
feature(footer): Add theme configuration for the footerlink

Footer links are no more hard coded. new theme based on
c.rcse.mobile & c.rcse.desktop just a matter of configuration
fix(footer): add a forgotten file from previous commit
display(group tile): add effective date

The effective date is extracted in order of found date:
* effective_date
* modification_date
* creation_date
refactor(fontawesome): remove from this addon

font awesome for jquerymobile has been moved to
plonetheme.jquerymobile project