starting to develop the record button using part of guga's code (https://github.com/gugat/bbb-record-button)
the timestamps of the recording events are normalized now, matching the recording marks; still need more testing when there are multiple start-stop recording events; the whiteboard actions are already working, including the slides, but slides that are outside of the recording period are still being loaded in the svg file (#TODO)
Merge branch 'record-button' of github.com:fcecagno/bigbluebutton into record-button

Conflicts:
	record-and-playback/core/lib/recordandplayback/generators/events.rb
refactored a little bit the function translateTimestamp; the images that are never displayed aren't included on the svg file anymore; still have to figure out the issue with the shapes made BEFORE start the recording - for now we cannot differentiate shapes made on the current slide and the ones made on a previous slide before start the recording