Bug fix in task start/finish lines
A pilot using xcsoar software a few days ago reported a problem with the task startline not being accurate at the borders.
It seems that the error depends on the fact that, as the pilot explains, the start line is not 90 degrees exactly to the target point.
We assume the same can happen with the finish line.

In case the start/finish lines are very big, like 20km long, and the first target point is far away, over 50km, then the error can be measured in some dozens meters.
With shorter start/finish lines, the error is relatively smaller, and become unnoticable.
This problem in fact has been in both softwares for 8 years, and nobody could discover.

The condition to discover the problem, in fact, is to cross the line at the borders, which is a "borderline" condition intrinsecally.
It is risky in any case, because the GPS on LK (or xcsoar) cannot be hold valid in case the position fix is wrong by a few meters, resulting in a no-start or a no-finish.

Anyway, we now reduce a bit the length of these lines, depending on their sizes and distance to next turnpoint.
This is now fixing the calculation problem, but it is nevertheless granting 4 times more marging than a calculation fix, assuming that the pilot that wants to cross the lines at their borders can have a gps which can be even a dozen meters wrong, while turning for example.

Here are some examples computed automatically by LK to make some margins on the borders, depending on the line size and distance to next turnpoint:

LINE LEN  DISTANCE TO NEXT         CORRECTION ON LINE LEN
2 km        25km		      8 m
10 km       20km                     33 m
10 km       60km                     99 m

Which means that if you have a 20km start line (10km on each side of the start point), in that case it will be shortened by 99m on each border for your safety. A glider flying at 120kmh will make 33 meters every second, and the gps is always 1 second late.
For this reason LK will be conservative on the borders, for those that need to cross start of finish risking in any case a false start/arrive.
Update changes, and fix the previous commit typo in the comment> "this is now fixing" should read "this is not fixing..".
Bug fix in task start/finish lines
A pilot using xcsoar software a few days ago reported a problem with the task startline not being accurate at the borders.
It seems that the error depends on the fact that, as the pilot explains, the start line is not 90 degrees exactly to the target point.
We assume the same can happen with the finish line.

This patch is fixing the calculation of the angle, by applying the Great Circle convergency which was not taken into account.
Revert commit 8a866e0d945f631e1d68b53f108caa631ea38d4b  since we now fix the angle, not the line borders.
Fix problem in replay logger while dealing with position fixes in the IGC file having the same timestamp.
It was causing an assertion failure.
Update changes.
. Remove ProjectedTrack dash line for AAT tasks.
+
. Add "Position" button in SIM mode PAN mode.

To reposition the aircraft in sim pan mode, simply change position by dragging the moving map, and when the center cross is
where you want to position the aircraft, click on the "Position" new button on left top screen.
The old behaviour was to long click on the moving map, but it was not working fine on PNAs, and it was inaccurate.
Now that we have a smooth scrolling, it is better to use a button.
The old function for repositioning is no more available.
XCI has changed, update DEFAULT_MENU
Update changes