More explicit dockerbuild output
Standardize agent help + add replace command
Standardize harpoonctl timeouts and flag orders
More flag-fixing in harpoonctl
Improve harpoonctl replace
A test payload for harpoon.

This is based on Bazooka's Rocket.  It operates as a batch program
or an http server.  It can leak memory, run out of memory, terminate
with user specified error codes, or serve messages.

This will replace busybox in our integration tests.
Merge branch 'master' of github.com:soundcloud/harpoon into use-warhead

Conflicts:
	warhead/main.go