fixes in SAT/polyhedral contact clipping, avoid adding GJK contacts (the contact margin causes different contact depths)
add polyhedral convex shape in InternalEdgeDemo as example of the new SAT/polyhedral contact clipping (added reference to Manual/what's new)
avoid glueing objecs with contacts that are positive (no gaps)
It assumes a btCompoundShaps (where the childshapes are the pre-fractured pieces)
The btFractureBody is a class derived from btRigidBody, dealing with the collision impacts and connectivity/propagating the fracture.
Press the F key to toggle between fracture and glue mode
This is preliminary work, can be used as a starting point to implement your own fracture.