NEWS.txt: prepare version 6.5.2
po: update Polish translation
po: update Finnish translation
AbstractTaskFactory: more API documentation
Dialogs/TaskPropertiesPanel: hidde FAI finish height if not a FAI task
GlueMapWindowDisplayMode: Check availability of heading for DisplayMode::HEADING_UP

Fixes trac issue #2662, #2663.
GlueMapWindowDisplayMode: Simplify code

Don't try to handle non-availibility of basic.track for
DisplayMode::TRACK_UP in if branch of DisplayMode::NORTH_UP.
test/harness_task: obtain task factory handle after SetFactory()

Fixes valgrind warnings and false negatives.
MainWindow: disable gestures while modal dialog is shown

Fixes random freezes because the MainWindow was capturing all touch
events (TRAC #2664).
Android release v6.5.1b

Ship the fixes for the two Android-specific freeze bugs quickly to our
users.
Merge tag 'v6.5.1b'
MAT Task support

[mk: code imported from TopHat 0.1.3_beta]
AbortTask: move types out of the class

Will help reduce header dependencies.
AbortTask: move AbortIntersectionTest to a separate header
TaskManager, OrderedTask: rename the writable GetTaskAdvance()

Rename to SetTaskAdvance() to make it clear that this is about
writing.
TaskManager: remove GetTaskAdvance()

This read-only accessor is not necessary, better use GetOrderedTask()
directly.
test/RunTask: force-arm the TaskAdvance object
OLCTriangle: solve triangles with a closing point pair unequal to takeoff/landing point

Fixes analysis of http://www.skylines-project.org/flights/13200/

The previous solution was not complete, so this one should be better.

Needs the following commit to work, because the legacy code still
has a small bug.
OLCTriangle: return length of second leg, not of both second and third