Do not filter out interfaces if run inside a container (#934)
* Do not filter out interfaces if run inside a container
If conjure-up is run inside a single lxd container then all network interfaces
are presented as virtual. The best approach to fixing this is to whitelist 'eth'
as this is the pattern for network device naming within containers. So for now
we check if virtual or if the device name doesn't start with eth.
fix logger and print output in hooklib writer (#939)
Eventually, I'd like to remove hooklib in favor of seperate modules like sh and
env to assist users in writing spells. Also to reduce maintenance burden.
