Ability to exit a Step chain before finishing all registered steps

lib/step.js

@@ -118,6 +118,10 @@ function Step() {
     };
   };
 
+  next.exitChain = function () {
+    steps = new Array();
+  }
+
   // Start the engine an pass nothing to the first step.
   next();
 }

test/exitChain.js

@@ -0,0 +1,25 @@
+require('./helper');
+
+var selfText = fs.readFileSync(__filename, 'utf8');
+
+// This example tests stopping a step chain before running all the registered steps
+
+expect('one');
+expect('two');
+Step(
+  function readSelf() {
+    fulfill("one");
+    fs.readFile(__filename, 'utf8', this);
+  },
+  function capitalize(err, text) {
+    fulfill("two");
+    if (err) throw err;
+    assert.equal(selfText, text, "Text Loaded");
+    return this.exitChain();
+  },
+  function showIt(err, newText) {
+    expect("three");
+    if (err) throw err;
+    assert.equal(selfText.toUpperCase(), newText, "Text Uppercased");
+  }
+);