Changes enumeration of elements and basisfunction to consistent scheme

[VikingScientist]

The element reordering as it stands is currently optional, but the basisfunction reordering is forced. This is because any call to LRSpline::generateIDs() will overwrite the enumeration given by LRSpline::renumberBasisfunctions(). generateIDs() is frequently called, for instance during write-to-file, so I couldn't find a good way around this. Let me know if you have any suggestions.

Hopefully this will not break any downstream applications such as IFEM, but it is not unthinkable that it is going to since the new enumeration scheme is forced.

[VikingScientist]

As requested @TheBB

[TheBB]

Wow, I didn't expect this so quickly.

Will try to build the python bindings against this, at least.

[VikingScientist]

Rebased on #42 which will be merged shortly