move guide under docs/
add guide around using public forks
move Owners team info to the sandboxing guide
list tradeoffs for repo setup options
point out that forking method can use PRs
highlight keywords in student steps
use 1's for all ordered lists
fix feature capitalization
only use a single space between sentences
incorporate feedback from @neverett
change signup link to go to help doc
explain option of using private repositories with forks

split out information around requesting and setting out private repositories, to be used by both fork and sandbox strategies
centralize instruction around creating user accounts
reword the 'why forking' part
link to git-ref for information on git commands
link to markdown for copying student steps
Merge remote-tracking branch 'origin/master' into public-repos

Conflicts:
	guide.md
fix validation for split guides
reword sentence around creating accounts
fix links between guides