EVR-CP: Repaint only when necessary when paused.

Additionally this seems to fix backward frame-stepping.

This commit fixes #4036.
MainFrame: tweak overridden Alt key behaviour

When menubar has focus, we don't receive WM_SYSKEYDOWN messages, only
WM_SYSKEYUP messages. Overriding only show menubar behavior is
reasonable compromise.
Stop mouse hider when entering menu modal loop

We don't receive WM_MOUSELEAVE message until the loop exits
otherwise
Controls: properly remove unused hide ticks

Otherwise we may stay subscribed to periodic timer without a need to
PPageFullscreen: dirty when changing hide policy
Don't exit "delay show not loaded" state on show
Don't paint logo in "delay show not loaded" state
We herd ya liked reverts

This reverts commit 36adc3a8e3bcb3e3408db9349b65fe9d2ca66e1e.

Maybe one day it will go upstream in one form or another.
Controls: redraw after recalc layout

Video renderers paint messages may delay controls redraw otherwise
Don't read media flags in "delay show not loaded"

They can be whatever
Seekbar: fix possible memory leak
MainFrame: repaint evr when requested
Settings: place all osd settings in one struct
Osd: new implementation
Osd: switch to new implementation
Osd: use our own madvr exclusive mode notification
Seekbar: prepare for new exclusive seekbar
MainFrame: fix taskbar clip area calculation