#181 Fix navigation when waypoint is edited

[Anonymous]

Originally created by: joachim....@gmail.com

What steps will reproduce the problem?
1.  select "Navigate to" on an arbitrary waypoint WP
1a. distance and angle to WP are shown in the map
2.  select "Edit" on WP, change coordinates
3.  distance and angle still target the old coordinates
    though the WP is updated on the map

What is the expected output? What do you see instead?
Distance and angle should be updated, when leaving the edit screen.

What version of the product are you using? On what operating system?
Recent SVN version.

Please provide any additional information below.
A suggested patch is provided.