Cleaned code for logm_layout_general. Changes include:
- Vertex renaming is no longer done when complete graphs are generated since they are already named properly
- Creation of T* track no longer requires the list t_list in order to properly bend all the vertices
- Code is now limited to 79 characters wide

Added rootnbyrootn.py (modified logm layout plugin), which is an implementation of 3DPSE_p from Point-Set Embedding in Three Diensions by Henk Meijer and Stephen Wismath (2012)
- Can create a complete graph and also use any graph as input
- Does not use L' as in algorithm in paper, but only uses L'' at instead (0,0,logm) to (m-1,0,logm) to decrease depth to 1+logm