[BUG] [PLAYER] Framestepping does not go back to frame 1

[Nepster]

Bitbucket: https://bitbucket.org/namida42/neolemmixplayer/issues/5/cannot-backwards-skip-to-frame-0-or-frame

If one plays a level and uses the frame-skipping hotkeys to go back to the very beginning of the level, one only gets back to frame 2, but not to frame 0 or 1. In usual levels this does not cause any problems. However if there are preplaced lemmings, one can assign them skills on frame 1 or frame 2.
Because replays are persistent over exiting the level to the result/preview screen, there are only two possibilities to remove these skill assignments:
1) Start the level again from the preview screen, pause at frame 0 (or frame 1 if the skill assignment is only on frame 2) and then cancel the replay. 
2) First go to another level and then go back to the level you originally wanted to play.

There should be a simpler way to do this. The easiest way is to allow frame-stepping back to frame 0 (and disallow skill assignments on frame 0).

[namida]

There's no explicit prohibition of going backwards to frame zero, but it's very possible there's something indirectly causing it.