Summary:
Documented all exposed Sandy APIs plugin developers should know about.
Honestly didn't proof-read it myself yet, but wanted to publish this diff at least before PTO, so that the information is available to anyone interested / playing with sandy
Reviewed By: jknoxville
Differential Revision: D22976373
fbshipit-source-id: c30918201d2feeb306ca0d9a3ae1ec10bdf7e2f5