OSX: Marker Details data are now bound to the UI controls.

- Fixed bug with buttons where the mouse over status would not be
cleared when clicking the button
- Marker details are now displayed correctly but not actually saved
- Added messages for loops and segments, plus a new message to indicate
when a marker is edited (the MarkerDetails is no longer a different
dialog, so it is part of IMainView and requires a message to be
refreshed).