As the engine clusters are intened primarly for interface with other SSTU parts (which have their own mount and fairing code), I will be moving the engine clusters over to have 'None' as the default mount in the editor/etc.

This change will more easily facilitate using the mounts with SSTU fuel tanks and Upper Stages, which have their own mount and fairing setup.

Cancelled - The mounts look nice in the editor, and the only reason for the default 'none' is really for upper-stage compatibility.