added default controller class
fixed command parameter
set DefaultController as the mininet class default
restructured defaultController into a function
revised comment on defaultController function
removed bookmark
Merge branch 'devel/defaultController' of https://github.com/cdburkard/mininet into cdburkard-devel/defaultController

Conflicts:
	bin/mn
	mininet/net.py
Merge branch 'cdburkard-devel/defaultController'