Support for HID-based partial super-fast flashing (#523)

* fix bug

* Fixed an issue where the Game of Life menu item was not appearing (#497)

* Starting on dapjs flashing

* Adding dapjs

* Connected

* Flashing works

* Double buffer flashing

* Add SHA computation function

* Run SHA code

* Swap SHA for murmur+crc

* Switch to dual murmur3

* Partial flashing works

* Remove unused code

* Move flashing code to external/sha

* Fix whitespace

* Cleanup binary genration scripts

* Add docs for hid flashing

* bump pxt-core to 0.12.132,

external/sha/module.json

@@ -0,0 +1,9 @@
+{
+  "name": "sha",
+  "version": "0.0.0",
+  "keywords": [],
+  "author": "",
+  "license": "MIT",
+  "dependencies": {},
+  "bin": "./source"
+}