Q Light Controller+

I just noticed a bug that crashes QLC+.

Steps to reproduce:
1. Open the attached workspace.
2. Go to the Show Manager.
3. Click on "Mac Movement"
4. Click on the Clock icon on the right side (not at the top)
5. Set the duration to 0 by clicking the minus button.

This happens only in the Show Manager, not in the Functions Manager.

I'm using 4.10.2b on windows 10

I've fixed the crash in git. It still allows zero duration, but at least doesn't crash.
Next step would be to disallow zero duration (it doesn't make sense for EFX).