Add support for drag and drop between pyfa displays which explicitly support it (some other tweaks as well)
Fix recalc after module clone. Enforce module restrictions.
Improved on drag/drop for cargo and fitting views. Can now copy rather than swap
Merge branch 'cargoDrag' - adding improved drag/drop functionality.

fittingView was the only real view that had drag and drop, and that was to support module swapping. I tweaked the dragged data to include source so that other Views can use it. Supported drag/drop:

* Copy / Move / Swap module from fitting to cargo
* Drag market items to fitting and other views
* Probably more that I cannot remember
Fix regression