Adding docs and examples for the LED pins

eg/onboard-led.js

@@ -0,0 +1,19 @@
+// global.IS_TEST_ENV = true;
+var Tessel = require("../lib/tessel.js");
+var board = new Tessel();
+
+board.on("ready", function() {
+  console.log("Ready");
+
+  var leds = ["L0", "L1", "L2", "L3"];
+
+  leds.forEach(function(pin) {
+      this.digitalWrite(pin, this.HIGH);
+  }.bind(this));
+
+  setTimeout(function() {
+    leds.forEach(function(pin) {
+        this.digitalWrite(pin, this.LOW);
+    }.bind(this));
+  }.bind(this), 1000);
+});

readme.md

@@ -33,6 +33,7 @@ board.on("ready", function() {
 ```
 
 ## Pin Naming Guide
+There are two primary ports on the Tessel2: Port "A" and Port "B".  There is also a bank of onboard LEDs which are controllable from a port we are calling "L".  Note that "L0" and "L1" should be reserved for system functions (ERR and WLAN) so you should avoid using them.  Instead, consider using "L2" and "L3" which are intended to be more informational in nature.
 
 | Port | Number | Johnny-Five Compatible Name |
 |------|--------|-----------------------------|
@@ -52,6 +53,10 @@ board.on("ready", function() {
 |B|5|`"b5"` or `"B5"`|
 |B|6|`"b6"` or `"B6"`|
 |B|7|`"b7"` or `"B7"`|
+|L|0|`"l0"` or `"L0"`|
+|L|1|`"l1"` or `"L1"`|
+|L|2|`"l2"` or `"L2"`|
+|L|3|`"l3"` or `"L3"`|
 
 See [examples](https://github.com/rwaldron/tessel-io/tree/master/eg) for basic, non-Johnny-Five examples.
 
@@ -80,6 +85,10 @@ See [examples](https://github.com/rwaldron/tessel-io/tree/master/eg) for basic,
 |B     | 5   | ✓           |     |     |     |      |      | ✓  |    | ✓         |            |
 |B     | 6   | ✓           |     |     |     |      |      |    | ✓  | ✓         |            |
 |B     | 7   | ✓           |     |     |     |      |      |    |    | ✓         | ✓          |
+|L     | 0   | ✓ (out only)|     |     |     |      |      |    |    |           |            |
+|L     | 1   | ✓ (out only)|     |     |     |      |      |    |    |           |            |
+|L     | 2   | ✓ (out only)|     |     |     |      |      |    |    |           |            |
+|L     | 3   | ✓ (out only)|     |     |     |      |      |    |    |           |            |