Make Cone constructor with apex and base center locations + radius

[egpbos]

This may improve fitting, since these are a lot easier to interpret. Also visual / manual fitting might be easier with these parameters than by fiddling around with angles. This is probably the reason Mathematica uses these construction parameters instead of the set we currently use (height, radius, two angles, base position x, y, z). Note that in both cases we have 7 parameters for the cone.

[egpbos]

Cleanest way to do this is probably with classmethod factories: https://stackoverflow.com/a/682545/1199693