show recurrence icon (frontend) (issue #627)
(new text: COM_JEM_RECURRING_EVENT, COM_JEM_RECURRING_EVENT_DESC, COM_JEM_EDITEVENT_WARN_RECURRENCE)
Merge branch 'develop' into feature/recurrence

Conflicts:
	site/common/views/tmpl/default_events_table.php
	site/views/editevent/view.html.php
remove saved event from recurrence set or dissolve set (issue #627)

When an event is saved it is always removed from a recurrence set.
Also a complete recurrence set is dissolved if this is the first event.
show recurrence icon / warning (backend) (issue #627)
fix undefined property (issue #636)
New content plugin to dissolve recurrence
 if first event is deleted (issue #627),
add version check to package (issue #632)
Merge branch 'develop' into feature/recurrence
edit event: warning text improved (issue #627)
fix Joomla 3.x check for package (issue #632)
fix little typos
recurrence: diff. icon / text for first event (issue #627)
editevent: split recurr. warning (issue #627)

split into title and text to allow formatting inside tmpl file
also both "<br>" and "\n" are possible in language file
auto-creation: set correct state on new events (issue #627)

new event is published if reference event is archived or trashed
recurrence wording, little fix backend.css (issue #627)
Merge branch 'develop' into feature/recurrence
Merge branch 'feature/recurrence' into develop
prevent wrong introtext (issue #628), use empty() for properties
make common layouts overridable (issue #630)
Merge pull request #641 from Hoffi1/develop

lot stuff (recurrence, pkg version check, introtext, overridables)