WinRT: made sure build script generates Release-built binaries, by default
winrtbuild.bat/.ps1 were generating Debug-built binaries, in some cases.
This change makes sure that Release mode is the default.
Windows: Always set the system timer resolution to 1ms by default.
An existing hint lets apps that don't need the timer resolution changed avoid
this, to save battery, etc, but this fixes several problems in timing, audio
callbacks not firing fast enough, etc.
Fixes Bugzilla #2944.