First complete draft of Sublime Text command line guide

Hi Erik,

I've finished the guide. All steps are now fleshed out. There are links. There are block quotes. There are code blocks. There are images. It's all very, very pretty. This is my first attempt at using markdown, but I quadruple-checked everything so I think everything is formatted as I intended.

By the way, I don't quite understand how this pull request stuff works so I hope this particular request includes the addition of an "images" folder.

-Jeff