accela: simplify
accela: resize form
filters: move icon to main app
move shortcut dialog to ui module
credit for contributor
accela: adjust constants for faster response

Tested-by: @KyokushinPL
ensure tray exists before minimizing to it

Issue: #104
update tray when changing setting through UI

Issue: #104
delete QLibrary, not force unload()

Issue: #96
Reported-by: @sasam

Also fixes a memory leak.
bind socket on worker thread for thread ownership
pt: set correct focal length from camera fov

Issue: #96

Having user-supplied camera fov, we can prevent yaw and pitch occuring
by itself when moving horizontally and vertically.

Note PointExtractor::extract_points(Mat& frame) should enable same value
for fx and fy:

			c[0] =  (mx/m - W/2)/W;
			c[1] = -(my/m - H/2)/W;