SH-4489 New debug/dev settings for control over new mesh behavior

While giving myself a full project code review, found a bug in
the MeshUseGetMesh1 setting.  Mostly defaulted to old configuration
but used the GetMesh2 caps which would have been a huge DoS
resource sink.  Did some documentation maintenance as well while
I was in there.  More for the to-do list, etc.