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/bluetooth/enums.d.ts

@@ -0,0 +1,21 @@
+// Auto-generated. Do not edit.
+
+
+    declare enum Delimiters {
+    //% block="new line"
+    NewLine = 1,
+    //% block=","
+    Comma = 2,
+    //% block="$"
+    Dollar = 3,
+    //% block=":"
+    Colon = 4,
+    //% block="."
+    Fullstop = 5,
+    //% block="#"
+    Hash = 6,
+    }
+declare namespace bluetooth {
+}
+
+// Auto-generated. Do not edit. Really.