The size of the various parts of the compass can now be easily modified

Mostly, removal of old code that had been commented out instead of
removed

- Corrected and cleaned up rotation calculation
- Fixed button position/size issues (clickable area didn't correspond to the button image)
- Fixed tool flashing during resizing
- (new feature) Buttons now scale proportionally to the protractor when it is resized
- Everything is now drawn by default at a scale of 1 instead of 1.5
- Pen width set to 0 (i.e always 1 pixel thick regardless of zoom), to keep the old look & feel
- Scaled the marker tool image (.svg) to look like it did before without scaling it in code
- Removed debug messages

Tested on OS X, works fine.

by "openboardtool://apps".

Q_WS_MACX -> Q_OS_OSX
Q_WS_MAC -> Q_OS_OSX
Q_WS_WIN -> Q_OS_WIN
Q_WS_X11 -> Q_OS_LINUX

Now oriented to Top.

Now, only one instance per scene is allowed in calling UBGraphicsCache instance() static function.