Add logs commands to access app logs via dokku client

[jimeh]

As the bulit-in dokku logs command only shows the output of supervisord itself, I created a few extra logs:* commands to enable accessing various app/process logs.

Additionally I had a bunch of random cleanup/reorg changes laying around from when I was bored that I threw in. No offense taken if you don't like my cleanup bullshit, and if so I can create a new PR with just the changes required for the logs commands :)

[danielepolencic]

+1

[dblock]

+1 here too, need any help with this?