Multiple sensors 2 (#877)

* Fixed -1 mode in libs

* Deleted todo

libs/color-sensor/color.ts

@@ -1,5 +1,5 @@
 const enum ColorSensorMode {
-    None = -1,
+    None = 0,
     //% block="reflected light intensity"
     ReflectedLightIntensity = 0,
     //% block="ambient light intensity"

libs/core/input.ts

@@ -212,7 +212,6 @@ namespace sensors.internal {
 
         _activated() {
             this.realmode = 0
-            // uartReset(this.port) // TODO is it ever needed?
             this._setMode(this.mode)
         }
 

libs/gyro-sensor/gyro.ts

@@ -1,5 +1,5 @@
 const enum GyroSensorMode {
-    None = -1,
+    None = 0,
     Angle = 0,
     Rate = 1,
 }

libs/infrared-sensor/ir.ts

@@ -1,5 +1,5 @@
 const enum InfraredSensorMode {
-    None = -1,
+    None = 0,
     Proximity = 0,
     Seek = 1,
     RemoteControl = 2,