Computation times

00:00.181 total execution time for 4 files from auto_examples/basic:

Example	Time	Mem (MB)
Directed Graph (plot_basic_directed.py)	00:00.082	0.0
Properties (plot_properties.py)	00:00.045	0.0
Simple graph (plot_simple_graph.py)	00:00.031	0.0
Read and write graphs. (plot_read_write.py)	00:00.023	0.0