Blender Git Loki

BGE: allow setting velocity to zero in a motion actuator.

The motion actuator goes out of its way to prevent setting zero velocities,
which should actually be supported. This patch just works around it as a
first test. We should investigate whether the flags
`m_bitLocalFlag.ZeroLinearVelocity` and `m_bitLocalFlag.ZeroAngularVelocity`
are actually needed/desired at all.

One of the issues that's already visible with this simple change, is
that objects aren't actually frozen but still move a little bit; see
test with {F241908}.

Reviewers: lordloki, hg1, moguri, panzergame

Reviewed By: lordloki, panzergame

Differential Revision: https://developer.blender.org/D1545