Bug fix in fitForward of velo-only Kalman fit
The Velo-only Kalman filter is not initialised properly in some cases for forward-fitted (i.e. backward) tracks, small improvement to the logic should fix.
Tested only in very nonstandard upgrade 2 configuration, so it would be good to have a check on performance for current conditions.
closes #490
Edited by Maarten Van Veghel