Revert "[WIN32] changed: set background mode when minimized. prevents screen saver to kick in."

This reverts commit 872d58c73dcb40f5f7bf71a2d1e4509e676f07e0.
Merge pull request #4623 from FernetMenta/background

Revert "[WIN32] changed: set background mode when minimized. prevents sc...
videoplayer: adapt lateness detection and dropping to buffering
video player: present correct pts to user for a/v sync (after buffering in renderer)
videoplayer: some rework and documentation
renderer: bump buffers to 5
videoplayer: update frametime, it might change due to fps detection
videoplayer: give streams with invalid fps a chance for fps detection
dvdplayer: allow rewinding at end of stream, do a seek after rewind
dvdplayer: observe pts counter overflow
dvdplayer: avoid short screen flicker caused by unnecessary reconfigure of renderer
vdpau: advanced settings for auto deinterlacing
player: fix rewind
pvr: increase changes counter of stream on stream change, cosmetics after dd307930d39d92f145a01a16600cd00e01ec39be
pvr: do not show selection dialog for a single menu hook
linux: use CLOCK_MONOTONIC_RAW as this is not subject to NTP
OMXPlayer: some caching fixes for pvr
fix incorrect display of fps when dr kicks in
renderer: allow some lateness within vblank interval
ActiveAE: slightly reduce buffer size