- renamed sigMoveToDateRequest to sigMoveToDate
 - added sigMoveToExtent
 - modified context menu

fixed example data loading

MapCanvas:
- setTSD now sets the map canvas QGIS temporal range as well (mit be used by layer styles)

mapvisualization.py: refactoring
MapWidget:
- shows slider date
- added .sliderDate(...)

temporalprofiles.py:
- refactoring
- fixed TemporalProfile.loadMissingData
- fixed TemporalProfileLoaderTask

Signed-off-by: Benjamin Jakimow <benjamin.jakimow@geo.hu-berlin.de>