#68 Do not unpause video when restoring window if it is not required

[Victor Tyazhelnikov]

Currently, SMPlayer can pause playback when its window is minimized, and 'unpause' it when the window is restored back. But it 'unpauses' it even if the video was not playing at the moment the window had been minimized. Such behavior can be irritating.

Expected behavior:
- the video is not playing;
- minimize the window;
- restore the window;
- the video should not be playing.

Actual behavior:
- the video is not playing;
- minimize the window;
- restore the window;
- the video is playing.

The patch below fixes the issue.