[ANN] core changes 2.2 -> 2.3

Following changes previously undocumented:

- Mapping now defaults to 0:180 if empty, no more empty mappings.
- Changes apply before clicking OK. Pressing Cancel cancels the changes.
- User interface got reorganized to be more compact.
- Can minimize to tray and start to tray in "keybindings" dialog.
- Can remap or disable axis from mapping -> options window.

- PT tracker lost its "dynamic pose resolution" functionality.
- Aruco tracker various improvements.
- FreePIE Android receiver added.
- Accela filter user-facing options changed to be more useful.
- Kalman and EWMA filters were improved.
- Octopus was fed.

-sh