Improve Fruchterman-Reingold implementation
Improve Fruchterman-Reingold implementation

Now uses NumPy broadcasting instead of using transpose, which is
often a bit faster.

drufat/vispy,Eric89GXL/vispy,ghisvail/vispy,michaelaye/vispy,Eric89GXL/vispy,drufat/vispy,ghisvail/vispy,Eric89GXL/vispy,michaelaye/vispy,drufat/vispy,ghisvail/vispy,michaelaye/vispy