Make OptimizeCommand compile views

Had this idea a while ago but dismissed it, but a request from the IRC channel reminded me of it. By making the `artisan optimize` command compile existing views (assuming they can be compiled) you can bring some load off your server or at the very least ensure that the first person to hit your website won't get a much slower response than the ones after him/her.

This is obviously not an issue for 99% of the framework's users, but I thought, why not?