Make both activities launchable from home screen
Don't exit activity during onPause

Before, the activity exited if the phone was rotated.
Checkpoint menu rework
Rework trail clear confirmation
Harmonise menus on the two activities
Add button to UI for route cutting
First small step in reorg of waypoints/linkages
Rework the confirm dialog for clearing the map trail
Use Pythagoras scheme to detect obtuse angles instead of scalar products
Restructure internal storage of the waypoints
Further improvements in waypoint management
Add support for cutting lines from the routing shown on the map
Save and restore struts to file
Merge branch 'activities'