Don't overwrite the .env.sample file if it exists

Previously when you run install it overwrites the file that's already there. If I install this into an app directory that already has a .env.sample I lose all the sample env vars for that app.
Move finding IP's and waiting for provisioning into functions.

These are going to be shared with plow.
Fix spelling.
Merge pull request #8 from MarkBennett/get-instance-up-with-or-without-subnet

Get instance up with or without subnet
Merge pull request #7 from jbabe/dont-clobber-existing-env-sample

Don't overwrite the .env.sample file if it exists