Debug builds were failing due to asserts in SimTK::Inertia (triangular test) and MassProperties (0 mass body cannot have nonzero inertia).  Added "verification" code to Body and eliminated from Model. We should throw Exceptions for bad inertia paramameters but given we still have gait models out there with whacked out toes (e.g. Sam's model) it shouldn't fail to run. This fixes #10.

For the time being there is also a check for the body being ground and to ignore its mass properties given in the properties since they are inconsequential. For some reason we have many model files with ground having zero mass and identity inertia.

We would not have inconsistent mass and inertia being set on ground if ground wasn't a listed Body in the model (XML) file. We should pursue that now that we can potentially connect geometry and other components to bodies via Frames. It makes more sense to list geometry and connect them to Frames. Then the display geometry and VisualObject and even WrapObject related methods could be removed, which would be great! We could use "ground" as a name/keyword for the base/ground reference Frame.

Although all test cases pass in release and in debug if using RUN_TESTS the following timeout:

2>  85% tests passed, 9 tests failed out of 60
2>
2>  Total Test time (real) = 3084.12 sec
2>
2>  The following tests FAILED:
2>  	 16 - testInitState (Timeout)
2>  	 35 - testOptimizationExampleRuns (Timeout)
2>  	 43 - testWrapping (Timeout)
2>  	 52 - testCMCArm26 (Timeout)
2>  	 53 - testCMCEMGDrivenArm (Timeout)
2>  	 54 - testCMCGait10dof18musc (Timeout)
2>  	 55 - testCMCSingleMuscle (Timeout)
2>  	 56 - testCMCSingleRigidTendonMuscle (Timeout)
2>  	 59 - testCMCWithControlConstraintsRunningModel (Timeout)
Merge branch 'master' of https://github.com/opensim-org/opensim-core into FixDebugBuild
improved clarity of check for masslessness
Merge pull request #151 from opensim-org/FixDebugBuild

Fix debug build to address issue #10