OLCTriangle: include finish point into search interval

The allowed points inside the closed trace is a closed interval
formed by [from, to], whereas a candidate set expects a
right-open interval of [from, to + 1).
OLCTriangle: relax shortest leg check a bit

The former 8/29 == 27.58% was a little bit too strict for some
border cases - this caused the algorithm to miss a better triangle
only if the origin of the flat projection was moved by some meters.
The new check 11/40 == 27.5% fixes that for the examined flights.
po: update French translation
po: update Swedish translation
DeviceBlackboard: explicitly cast enums to unsigned
AbortTask: add missing <vector> include
Makefile: remove duplicate CXX=clang assignment

Was in both llvm.mk and compile.mk.
po: update Japanese translation
po: update German translation
po: update Swedish translation
Makefile: move the "TESTING" flag to build/options.mk

Resolves a dependency problem: the variable was defined in android.mk,
but was used before that already in targets.mk.
debian/rules: add variable TARGET_OUTPUT_DIR

Allow overriding.
NEWS.txt: mention the new Kobo port
Form/List: fix pixel panning / e-paper check

This was the wrong way around.  D'oh!
release v6.7
NEWS: prepare for 6.7.1
NEWS.txt: remove remains of unreleased version 6.6.6

Development of 6.6.6 was cancelled due to the 6.7 release.
build: Fixed duplicate imagemagick call

This created issues in builds with high -j settings on some machines and
the convert-to-bmp-half function is expecting _1.bmp extensions which
created wrong output when fed with _2.bmp.
po: update Swedish translation
po: add Lithuanian translation