moving Tessellate towards more of a library structure

src/sketch.js

@@ -1,7 +1,7 @@
 
 export default class Sketch {
 	constructor(settings) {
-		this.lastTime = null;
+		this.lastNow = null;
 
 		['getContext', 'onResize', 'render'].map(method => this[method] = this[method].bind(this));
 
@@ -28,9 +28,12 @@ export default class Sketch {
 	}
 
 	render(now) {
-		this.draw(this.context, now, this.lastTime);
+		this.context.now = now;
+		this.context.lastNow = this.lastNow;
 
-		this.lastTime = now;
+		this.draw(this.context);
+
+		this.lastNow = now;
 		requestAnimationFrame(this.render);
 	}
 }