Added Clear Canvas function

Author: slizard00

lib/sketch.js

@@ -27,6 +27,15 @@ var __slice = Array.prototype.slice;
       return this;
     }
   };
+    $.fn.clear = function () {
+        var sketch = this.data('sketch');
+        if (sketch != undefined) {
+            sketch.context.clearRect(0, 0, sketch.canvas[0].width, sketch.canvas[0].height);
+            sketch.context = sketch.el.getContext('2d');
+            sketch.actions = [];
+            sketch.action = [];
+        }
+    };
   Sketch = (function() {
     function Sketch(el, opts) {
       this.el = el;