reorganize the site into topical sections

"Rules" for the operations of the channel
"Using" for how to get effective help using the channel
"FAQs" for frequently-asked questions
"Schools" for tutorials and beginner help
"Docs" for documentation, specs, and advanced help
new index content to get relevant content quickly
Merge pull request #12 from hashcss/reorg

Reorganize the Site [WIP]