Removing extraneous calls to MapCanvas::update()
Removing extraneous calls to MapCanvas::update()

Now that update() is being called automatically at a rate of 50 Hz,
the explicit calls in many locations are unnecessary.  It was also
possible for it to be called in some of these locations from a
non-main thread, which is invalid and could cause crashes.

evenator/mapviz,evenator/mapviz,jatowler/mapviz,jatowler/mapviz,swri-robotics/mapviz,swri-robotics/mapviz,pjreed/mapviz