UAVO browser was emitting updates on every UAVO receive event. This was
inefficient and led to a high processor usage, as well as causing the
browser to drop a high percantage of updates.

The patch centralizes the dataChanged emits, and places them on a timer.
UAVO browser processor load fell over 50% and data updates beyond 3Hz are
now reliably shown.
Updated updateChanged() throttling to act directly on view, instead of data.
Moved all awareness of update range to the tree view.