Generalize softbody limbs/joints

[acgaudette]

Remove deprecated limb-specific softbody Instance methods, particularly the box orientation() method Add general start and end methods for any Instance with index highlighting Remove other deprecated softbody methods Rewrite all softbody code to use matched_orientation()

Improve performance of Jacobi eigenvalue algorithm

• Add early exit
• Rewrite slow Mat3 get/set methods

Edit: Detect and handle duplicates in model input to softbody mesh generation Add base vertex to dynamic UBO (bugfix)

Additionally

• Improve performance of softbody simulation
• Add warnings for invalid shape matching transforms
• Deprecate box limbs
• Refactor softbody Instance