Inserting waypoints in Top View does not use "letter" labels

[Joern Ungermann]

There is an inconsistency between TableView and TopView in the sense that inserted waypoints get a fixed "letter" label in the TableView, but no label (respectively a changing numer) in TopView. This should be consistent. For iterating Flightplans with DLR-FX, using fixed waypoint labels is highly desirable.

[Reimar Bauer]

Resolve Issue #125

In addition added waypoints in Table mode get assigned a coordinate in between the preceding and following waypoint.

→ <<cset c0f64f7fdc0a>>

[Reimar Bauer]

Merged in joernu76/mss/issue125b (pull request #194)

Resolve Issue #125

→ <<cset 67d8f9e33b03>>