Weekly release v0.2.22

Summary:
Lots of work on React Native compiler.
Added a --check option.
Added --compatibility mobile option
Fixed double reporting of diagnostics.
Fixed #1235 and #979
Some refactoring

Reviewed By: simonhj

Differential Revision: D6838897

fbshipit-source-id: fbc472cac12203a87a925e7b25503cf77542e794

package.json

@@ -1,6 +1,6 @@
 {
   "name": "prepack",
-  "version": "0.2.21-alpha.0",
+  "version": "0.2.22",
   "description": "Execute a JS bundle, serialize global state and side effects to a snapshot that can be quickly restored.",
   "homepage": "https://github.com/facebook/prepack",
   "repository": {