Language preference: the selected audio track could be wrong after f771cec542a698ffdae7954d413a12e88bfeb93d.

Ticket #3316.
Modify SetupSubtitleStreams so that it's consistent with SetupAudioStreams.
Updated Ukrainian translation.
Updated German translation.
Rewrite mouse handling code (incomplete)

Fixes #1300, #1556, #2081, #3284
MainFrm: remove unused variable
D3DFS: remove horizontal margin from osd posbar

The bug with autohiding is now fixed and there's no reason to have it
there
Call OnIdle() less frequently
ChildView: remove unneeded critical section
PlayerNavigationDialog: minor refactoring