Catch internal exceptions and re-throw as MuscleCannotEquilibrate. Fixes testMuscles.
Catch internal exceptions and re-throw as MuscleCannotEquilibrate. Fixes testMuscles.

opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core,opensim-org/opensim-core