Graceful shutdown

Fixes #1: fishtank now handles SIGTERM to gracefully shut down apps (sending a SIGTERM to each one with a delay before Killing them)

- guppy now sends SIGTERM with a delay before killing run execs

- cause it's the circle.. the circle of life.

- added default nginx conf. and index.html incase you visit a fishtank with no projects (typically just after installing)

- fixed: nginx configuration wasn't reloading after adding a project

- guppy: disabled actually executing grunt. grunt is deprecated