Patches to fix race conditions in auto-alignment feature

[Raphaël Marinier]

Hi all,

I am a new user of kdenlive, and noticed arbitrary alignment of tracks
from time to time when using the auto alignment feature.
I investigated and found one race condition (and a couple of smaller
issues). I propose a fix with pull request
https://github.com/KDE/kdenlive/pull/6.

Please have a look and tell me what you think,

Thanks,

Raphael M.