EVR-CP: Repaint only when necessary when paused.

Additionally this seems to fix backward frame-stepping.

This commit fixes #4036.
Update SoundTouch to 1.8.0.
Update VirtualDub to v1.10.5-test2.
Use `void` instead of `VOID`.
Enable `/Qpar` compiler option.

Reference  http://msdn.microsoft.com/en-us/library/hh923900.aspx
Readme.md: add version badge.