Forcing ssh_wait is considered harmful.

1. If your Blimpfile is misconfigured, you'll not get any diagnostics information.
2. When you press Ctrl+C, blimpy doesn't exit because it's just ssh getting killed (and blimp ignores that)

There appears to be no provision for handling options, so I just made it a separate command
function like this touching ARGV is abstraction violation, as it prevents other driver code from legitimately launching interactive shell.

 Better to let the calling command handle this
allow monkey-patching of Blimpy by the project (mainly to add more commands)
don't waste a line if there's no need to

Blimpy prints unnecessary empty line if the SSH connection goes through
fast enough. Don't do it.
support a non-standard SSH port
debugger gem only works with 1.9 and forward
Merge pull request #73 from cloudbees/master

Bunch O changes