Update documentation for 2.0

[jpetrie]

Documentation-related stuff that should be improved before shipping 2.0:

• Make the script mode option more obvious in the up-front context (lower overhead, slightly more work than the "one click" native approach).
• Include installation instructions that use submodules (it's a better option if using script mode).
• Move the "recipes" information to the Github wiki.
• Move the "architecture" information to the Github wiki.