While the page numbers from BigBlueButton are zero-based, the slide images
are generated as 1-based.

This was added because BigBlueButton 0.9 started using 1-based page
numbers in the events.xml file. That change has been reverted, so as
to avoid behaviour changes from 0.81 in places where it's unnecessary.

 - subtract 1 from GotoSlideEvent and ResizeAndMoveSlideEvent to events.xml so that the recording is backwards compatible with 0.81 and earlier

 - add current time on header of JSON messages so we can display the correct time instead of calculating from the timestamp

 - a meeting that has duration zero (runs infinitely) should be cleaned-up if no one has ever joined on it

The parameter custom_mode=[simple|extended] overrides the mode set by default in lti.properties

Recording updates merge

With the switch to a different clock source in red5, the timestamps
in the events file are no longer real-time, but are rather in
seconds since computer boot.

The timestamp in the meeting id is still realtime, so use that as
the start time. Calculate the end time by adding the meeting length
to the start time.

Remove shell scrollbars and improved mdiCanvas height binding

MainApplicationShell mdiCanvas height binded to the application height instead of its parent heignt.

Changes to the LTI componet

Added message to let administration know that monit will restart bbb-record-core and LibreOffice.  Tweaked the language for audio settings dialog.