Constraint COM pull forces incorrect with SD integrator - Redmine #2201

With the SD integrator, the reported constraint pull forces are only for the SD random update, so fully basically Gaussian distributed. This can not have caused unnoticed errors.

(from redmine: issue id 2201, created on 2017-06-08 by berkhess, closed on 2017-09-12)

• Changesets:
  • Revision 41fa5855 by Berk Hess on 2017-06-08T20:41:37Z:

Fix COM pull force with SD

The reported COM pull force when using the SD integrator was random
only. Now the pull force is summed over the systematic and random
SD update components.
A better solution is to not add the random force at all, but such
a change should not be done in a release branch.

Fixes #2201.

Change-Id: I10a56b30b952869396d170914bcbc0163299a1c8