profilevisualization.py: fixed error if TemporalProfile coordinate is out of extents7

mapvisualization.py:
- refactored QGIS syncing

EOTimeSeriesViewer:
- added close()
- added setCurrentSource(TimeSeriesSource)

timseries.py:
- fixed sensor mockup in SensorInstrument
- reorderer classes
- speed-up TimeSeries.showTSDs()
- implemented TimeSeries.findSource(...)
- TimeSeriesTreeView context menu can be used to open selected source images in QGIS

create_plugin.py:
- added example directory to plugin folder

eotimeseriesviewer/ui:
- cleanup icons
- modified qgsMapCenter.svg