SDL/Canvas: anti-aliased text in greyscale mode
Makefile: disable SDL_ttf on the Kobo build

Use libfreetype directly.  Our FreeType code has matured enough.
po: update Italian translation
po: update Polish translation
po: update Japanese translation
OS/FileDescriptor: set close-on-exec by default
Event/{EGL,Android}: merge the struct Event implementations

These two implementations are similar enough.
FlarmCalculations: fix iterator after erase()
IOThread: fix iterator after erase()
Event/EGL/Queue: move code to class LinuxMouse
Event/Linux/Mouse: use FileDescriptor::Read()
IOThread: move code to new class IOLoop
Event/EGL/Queue: move code to class TTYKeyboard
Event/EGL/Queue: use class IOLoop

Allows plugging more I/O events.
Makefile: preserve the Raspberry Pi -march=armv6j option with clang

clang generates ARMv7 code when even "-target armv6-..." was
specified.
Screen/Window: allow calling Invalidate() only from main thread

Invalidate() was never truly thread-safe.  Only one caller actually
used it from another thread: the DrawThread via DoubleBufferWindow.
We're now using SendUser() / OnUser() instead.
DebugReplay: split CreateDebugReplay to allow calling with file name instead of args.
DebugReplay: move NLineReader out of DebugReader class

Prepare creating a DebugReplay from a std::vector.
skylines: tool to read igc file to std::vector

This is intended for a future python api to xcsoar. Therefore the
simple FlightFix struct which will be used to share a igc file
between xcsoar and python.
FlightFix: add availability flags