Surface declutter - issue #294

Removing various clutter from surfMesh and triSurface
- unused classes/files (backup copies on non-release repo)
- relocate some triSurface-related classes to where they make more sense, and where they can be reused.
- improve handling of various face types in MeshedSurface and UnsortedMeshedSurface (to bridge the gap to triSurface)
- improve transfer methods for reclaiming/reusing surface allocations

See merge request !77