Cleaned up _read_network in io.py; made more efficient, easier to read.
Cleaned up _read_network in io.py; made more efficient, easier to read.

yvesalexandre/bandicoot,yvesalexandre/bandicoot,econandrew/bandicoot,econandrew/bandicoot,yvesalexandre/bandicoot,ulfaslak/bandicoot,ulfaslak/bandicoot,econandrew/bandicoot,ulfaslak/bandicoot