Problem & ProcessorMotion initialization
Created by: joanvallve
Mostly, we want to add a initial covariance to the problem. To do this, there is the CaptureFix (we can change its name), adding it to the first frame and processing it, it creates a constraintFix.
But the ProcessorMotion::setOrigin(vectorXs state, ts) creates a key frame that should be the first, also. Maybe it should accept a frame instead of a ts...?