Move JobHandler away from VideoStatus
Cache current frame to avoid grabbing it twice
Start making threads wait for each other
Make all jobs progress together
Avoid grabbing previous frame twice in the job
Initial "wait for the video" support
Create BaseTarget class
Move trajectory calculation to JobHandler
Replace allFinished signal by QThread's finished
Fix bug that makes many jobs be left unfinished

..thus making the thread run forever.
Less unnecessary thread locking.
Use queued connection
Avoid segfault while JobHanlder is running
Merge branch 'centralize_calculation'

Conflicts:
	src/model/jobs/basejob.cpp