bringing back show ports (#377)

* bringing back show ports

* added firmware links in docs

* updated color rendering

* better rendering of touch/ultra/ir

* better data per sensor

libs/ultrasonic-sensor/ultrasonic.ts

@@ -18,6 +18,7 @@ namespace sensors {
             super(port)
             this.promixityThreshold = new sensors.ThresholdDetector(this.id(), 0, 255, 10, 100); // range is 0..255cm
             this.movementThreshold = 1;
+            this._setMode(0);
         }
 
         _deviceType() {
@@ -28,6 +29,10 @@ namespace sensors {
             return ((this.getNumber(NumberFormat.UInt16LE, 0) & 0x0fff) / 10) >> 0; // range is 0..2550, in 0.1 cm increments.
         }
 
+        _info(): string {
+            return `${this.distance()}cm`
+        }
+
         _update(prev: number, curr: number) {
             // is there an object near?
             this.promixityThreshold.setLevel(curr);
@@ -38,7 +43,7 @@ namespace sensors {
         }
 
         /**
-         * Registers code to run when the given color is close
+         * Registers code to run when an object is close or far
          * @param handler the code to run when detected
          */
         //% help=sensors/ultrasonic/on-event