SEISMICDESIGN-187: Convert region-specific red map overlays to layers that can be toggled on/off
Added layerControl to RegionController object.
Changed access to GlobalMapView._layerControl to use GlobalMapView.getLayerControl() instead.
Changed references for GlobalMapView._map to GlobalMapView.getMap()
Merge pull request #20 from aanderson-usgs/SEISMICDESIGN-187

SEISMICDESIGN-187: Convert region-specific red map overlays to layers th...