random division direction not normalized

[drbergman]

if not division function is defined, the rand_vec is created using UniformOnUnitSphere. This vector, in both 2D and 3D sims, is not guaranteed to be orthogonal to the state.orientation vector of the cell, meaning that the dot product here:

rand_vec[0]*state.orientation[0] + rand_vec[1]*state.orientation[1] + rand_vec[2]*state.orientation[2]

is almost always nonzero. This means any cell with nonzero polarity (e.g., all cells in a 2D sim) will have their rand_vec adjusted by this. So, we need to normalize in this case as well.

#387 fixes this as well as another bug in division placement