SF Features#76: Add ability to handle and name trackpoints.

SF Features#76: Add ability to handle and name trackpoints.

Normally these are more useful for named routepoints, but applies to trackpoints as well.

Process named points in GPX files.
Extend .vik files to save named trackpoints.

Rework Trackpoint dialog to display and make trackpoint name editable.
Shift the TrackWaypoint name into Trackpoint dialog title.

Extend the statusbar to display trackpoint name when selected trackpoint has a name.