Fix tabbing issue in editor on Mac. Also use `as` pattern in Turtle example.
Make syntax docs match implementation on associativity of user-defined
operators.
Merge branch 'master' of https://github.com/evancz/elm-lang.org
Merge branch 'dev' of https://github.com/evancz/elm-lang.org into dev

Conflicts:
	resources/misc/editor.js
Fix merge error in editor.js