first draft of documentation update

[ziel]

Main Changes:

• Adds a docs directory with some new docs
• Consolidates existing documentation there
• Extends the main readme with links into docs

@bhny -- I moved the document you wrote to docs/files.md to consolidate it with the rest of what I was writing. Is that ok?

The new docs are correct to the best of my knowledge, but as I'm still pretty new to this, they might be off... Corrections and suggestions are awesome.