Abandon Aruba; use straight RSpec instead. Add specs for the Server command.

Signed-off-by: David Celis <me@davidcel.is>
Use Rack::Server instead of Kernel.exec

Instead of hacking together a call to `Kernel.exec`, use Rack::Server

Signed-off-by: David Celis <me@davidcel.is>
Add tests for the Console command

Signed-off-by: David Celis <me@davidcel.is>