Task/TaskFileSeeYou: Handle trailing ',' in task entries

Some versions of StrePla write a trailing ',' in task entries, e.g.

"KORBACH/SCHWARZENBACH","KEMPEN","KEMPEN","KORBACH","SCHWARZE","KEMPEN","KEMPEN",

Handle this case correctly.
Android/I2Cbaro: close the EOC DigitalInput

Fixes "java.lang.IllegalArgumentException: Resource already claimed"
when pressing the reconnect button.
Pass line width in the correct unit

The parameter lw (start/finish line width) of the vlapi, expects as
value the line width (not radius) in km not in meters.
Make DAEC_KEYHOLE available to declarations

...so the correct waypoint type for a racing task in German competitions
can be written to devices who support it (i.e. Volklogger).
The actual handling by the Volkslogger driver will be a separate patch.
Volkslogger DAEC-Keyhole Declaration

Make the Volkslogger driver handle DAEC-Keyhole-Waypoint Types for
declarations.
StandbyThread: add method LockStop()
StandbyThread: allow Trigger() while busy

This will call Tick() again after the current iteration has finished,
with no delay.
AirspaceParser: move code to ParseBearingDegrees()
AirspaceParser: use ParseDouble()
XML/DataNode: use ParseDouble()
Dialogs/XML: use ParseDouble()
AirspaceParser, AngleDataField: omit the optional ParseDouble() parameter

nullptr is the default value.
Util/NumberParser: work around mingw64 wcstod() bug

mingw64 version 3.1 crashes when the "endptr" argument to wcstod() is
nullptr.  This patch adds another wrapper function which passes a
dummy parameter instead of nullptr.  This fixes instant crashes of our
6.7.4 PC binary (TRAC #3284).
Makefile: revert to gcc on Android-ARMv6

Workaround for TRAC #3339 due to LLVM bug.
po: update Romanian translation
po: update Slovak translation
release v6.7.5
Merge tag 'v6.7.5'
Apple/InternalSensors: Fix compilation with FIXED=y

Add fixed casts for assignment of double values to variables of type
fixed
Apple/InternalSensors: Add location data validity checks

According to Apple's CLLocation Class Reference, the longitude and
latitude values are invalid, if horizontalAccuracy is negative, the
altitude value is invalid, if verticalAccuracy is negative, and the
course value is invalid if negative.