Refactor to separate content

[ngoodman]

Separate the content .md files from the scripts and resources.

The scripts repo should have a build script that takes a folder location as input, builds all .md files in that directory, optionally builds an index if there is a chapters.txt file, and puts the generated html and all runtime scripts into a new subdirectory. (Runtime scripts might be just one merged and minified js with all the scripts?)

Ultimately we should move the chapter md files to a separate repository, but for now can just move them to a subdirectory.