scratch like broadcast api (#1358)

* scratch like broadcast api

* always register handler

* adding docs

* added icon

* updated block name

* adding DAL support "radio.raiseEvent"

* typo

* implemented using radiobus

* adding docs

* adding raise event block

* updated shims

* updated pxt

libs/radio/_locales/radio-jsdoc-strings.json

@@ -16,6 +16,7 @@
   "radio.onReceivedNumber": "Registers code to run when the radio receives a number.",
   "radio.onReceivedString": "Registers code to run when the radio receives a string.",
   "radio.onReceivedValue": "Registers code to run when the radio receives a key value pair.",
+  "radio.raiseEvent": "Sends an event over radio to neigboring devices",
   "radio.receiveNumber": "Reads the next packet from the radio queue and returns the packet's number\npayload or 0 if the packet did not contain a number.",
   "radio.receiveString": "Reads the next packet from the radio queue and returns the packet's string\npayload or the empty string if the packet did not contain a string.",
   "radio.receivedBuffer": "Returns the buffer payload from the last packet taken from the radio queue\n(via ``receiveNumber``, ``receiveString``, etc) or the empty string if that\npacket did not contain a string.",

libs/radio/_locales/radio-strings.json

@@ -10,6 +10,7 @@
   "radio.onReceivedNumber|block": "on radio received",
   "radio.onReceivedString|block": "on radio received",
   "radio.onReceivedValue|block": "on radio received",
+  "radio.raiseEvent|block": "radio raise event|from source %src=control_event_source_id|with value %value=control_event_value_id",
   "radio.receiveNumber|block": "radio receive number",
   "radio.receiveString|block": "radio receive string",
   "radio.receivedSignalStrength|block": "radio received signal strength",