give instructions to install deps after creation

[brianleroux]

if we're going to give output lets make it useful

current:

#! arc-gen-beta auth -d cool
Welcome to the Architect Generator Beta
run this command with --help to see info
created auth example

this would be much better:

#! arc-gen-beta auth -d cool
Successfully generated auth. Install deps are preview by running:

cd /Users/brianleroux/cool
npm i
npm start

also look into putting console output thru stderr so we don't fuck up piping