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/devices/pxt.json

@@ -0,0 +1,24 @@
+{
+    "name": "devices",
+    "description": "The BLE specific services",
+    "files": [
+        "README.md",
+        "enums.d.ts",
+        "shims.d.ts",
+        "devices.cpp"
+    ],
+    "public": true,
+    "dependencies": {
+        "core": "file:../core"
+    },
+    "yotta": {
+        "config": {
+            "microbit-dal": {
+                "bluetooth": {
+                    "enabled": 1
+                }
+            }
+        }
+    },
+    "installedVersion": "ljipgq"
+}