PPageFormats: minor fixes.

- Make it high-dpi aware.
- Make "Set as default program" button accessible for regular users.
Video renderers setting changes

- Mark VMR-7 (renderless) as unavalible on 64-bit build. (required libs
  are unavalible)
- Restore default renderer if unavalible was selected when loading
  settings
- Change default renderer on XP to VMR-7 (renderless). It will fallback
  to system default one (VMR-7 windowed) if it fails. This change will provide subtitle
  support with default settings.
- If EVR is not avalible on Vista+ select VMR-9 (renderless) instead of
  system default one. Again it will fallback when needed, and in fact it
  should never fail.
Fix typo introduced in 8ae02c6203ea3296406b88910bfdefbf80a8614e.
Add temporary flag to allow EC_VIDEO_SIZE_CHANGED event to stabilize
window size for 5 seconds since playback starts.