Fix T55589, T60967: Windows pen pressure issues at start/end of the stroke.

The new implementation uses WM_POINTERDOWN, WM_POINTERUP and WM_POINTERUPDATE
and the pointer API to process stylus events. This avoids the delays that comes
with the WM_MOUSE and WM_xBUTTON events. The implementation should work on
Windows 8, and Windows 10 with both legacy and new pen interaction.

It also changes how the pressure is reset when the Windows Ink implementation
is enabled. The previous version reset the pressure to full when the pen left
the screen, however for some hardware implementations this allowed a small
window where Blender may process the final move event and read the pressure
as full leaving a dot on the last event.

Differential Revision: https://developer.blender.org/D4314

Windows: add support for Windows Ink.

Before this Blender always needed the Wintab driver. This adds support for the
native pressure API in Windows 8+, making it possible to get pressure sensitivity
on e.g. Microsoft Surface hardware without any extra drivers.

By default Blender will automatically use Wintab if available, and if not use
Windows Ink instead. There is also a new user preference to explicitly specify
which API to use if automatic detection fails.

Fixes T57869: no pressure sensitivity with Surface pen or laptop.

Code by Christopher Peerman with some tweaks by Brecht Van Lommel.

Differential Revision: https://developer.blender.org/D4165

Fix T55589: drawing strokes with Microsoft surface pen misses first part.

This disables touch gesture recognition in Blender, avoiding any initial delay
when drawing with grease pencil, texture paint, etc.

Differential Revision: https://developer.blender.org/D4203