rename "microbit" package to "core" #414 (#270)

* rename "microbit" package to "core" #414

* shouldn't edit the package id.

* updating package.json

* updated the wrong version

* missed updating pxt.json of tests

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

@@ -0,0 +1,15 @@
+{
+  "radio.onDataReceived|block": "radio on data received",
+  "radio.receiveNumber|block": "radio receive number",
+  "radio.receiveString|block": "radio receive string",
+  "radio.receivedNumberAt|block": "radio receive number|at %VALUE",
+  "radio.receivedSignalStrength|block": "radio received signal strength",
+  "radio.sendNumber|block": "radio send number %value",
+  "radio.sendString|block": "radio send string %msg",
+  "radio.sendValue|block": "radio send|value %name|= %value",
+  "radio.setGroup|block": "radio set group %ID",
+  "radio.setTransmitPower|block": "radio set transmit power %power",
+  "radio.setTransmitSerialNumber|block": "radio set transmit serial number %transmit",
+  "radio.writeValueToSerial|block": "radio write value to serial",
+  "radio|block": "radio"
+}