Fix bug in getTotalCentrifugalForces() found by Justin Si and reported in issue #112.
Added some missing test cases which should have been there in the first place!

This was a localized problem in that reporting method; it didn't actually reflect the inertial forces that Simbody uses internally; those were correct.
Fix flop count in comment to reflect fix to calculation of getTotalCentrifugalForce() (it's cheaper now).
Merge pull request #116 from simbody/fixIssue112getTotalCentrifugualForces

Fix bug in `getTotalCentrifugalForces()` found by Justin Si and reported in issue #112.