lib.cli.Base.getConnection() & \@override _init_once()

two new stuff here:
1. lib.cli.Base.getConnection() which replaces request of new Paramiko connection each time. It will be reused instead.

2. _init_once() in cli.Base level. Whatever you want to be initiated once (keep in mind: setUp() of unitests.TestCase is invoked before _each_ test method) before tests run: do it right there - overriding the method.

... plus some subnet work (still not done, but really soon).