Add new field to generic event called register_url and hide Add calendar and Register buttons for past events

Solves #35 (Parametrize some fields of the google calendar entry..) but without parametrizing the time and date

Presentations title changed from h3 to h2 because the title font sizes have been normalized in the theme

Load presentations through Ajax (JS code was not being called) both in the modal and the ‘page to share’ windows

Reduce font size of Agenda button's title in dissemination view and remove unused macro to show page title

Solves #9 (Show overlay during page initialization so that navigation menu for mobile is not visible, uncollapsed)

Change scale image name to grid-teaser (#10 of sdswas.theme) and solves part of issue #24 (Perform automatic cropping of any image that has to be displayed with a specific aspect ratio)

Solves #23([BUG] Add to calendar and register buttons are missing in the Event modal window (Rodolfo template))

Allow images in generic event content type, show them in the full view with a boostrap carousel and solve a bug in the uninstall of the addon

Container content type SDS EVENT and contained content types WEBINAR, GENERIC EVENT and PRESENTATION