Weekly release v0.2.42: Debugability, speed, bug fixes

Summary:
Improved source location information
Only havoc abstract value args when really necessary
Debugger recognizes sourcemaps and opens the correct file/line when debugging in Nuclide.
Make React tests fast
Special case an expression simplification for Instant Render
Fix temporal assignments to intrinsics that happen inside non deterministic loops
Enhanced handling of Array.map applied to abstract arrays
Support dynamic invariants via __assume
We got a logo!
Add React Native mocks to Prepack

Reviewed By: simonhj

Differential Revision: D8739156

fbshipit-source-id: d535dfe0c5bcbee4aaed28f75d45cbedcc51344b

package.json

@@ -1,6 +1,6 @@
 {
   "name": "prepack",
-  "version": "0.2.42-alpha.0",
+  "version": "0.2.42",
   "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": {