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/core/serial.ts

@@ -0,0 +1,48 @@
+/**
+ * Reading and writing data over a serial connection.
+ */
+//% weight=2 color=#002050
+namespace serial {
+    /**
+     * Prints a line of text to the serial
+     * @param value to send over serial
+     */
+    //% weight=90
+    //% help=serial/write-line blockGap=8
+    //% blockId=serial_writeline block="serial|write line %text"
+    export function writeLine(text: string): void {
+        writeString(text + "\r\n");
+    }
+
+    /**
+     * Prints a numeric value to the serial
+     */
+    //% help=serial/write-number
+    //% weight=89 blockGap=8
+    //% blockId=serial_writenumber block="serial|write number %value"
+    export function writeNumber(value: number): void {
+        writeString(value.toString());
+    }
+
+    /**
+     * Writes a ``name: value`` pair line to the serial.
+     * @param name name of the value stream, eg: x
+     * @param value to write
+     */
+    //% weight=88 blockGap=8
+    //% help=serial/write-value
+    //% blockId=serial_writevalue block="serial|write value %name|= %value"
+    export function writeValue(name: string, value: number): void {
+        writeString(name + ":" + value + "\r\n");
+    }
+
+    /**
+    * Registers an event to be fired when a line has been received
+    */
+    // help=serial/on-line-received
+    // blockId=serial_on_line_received block="serial on line received"
+    // weight=21 blockGap=8
+    export function onLineReceived(body: Action): void {
+       // serial.onDataReceived("\n", body);
+    }
+}