misc comments

src/common/Class.js

@@ -37,5 +37,5 @@ Class.extend = function(members) {
 // adds new member variables/methods to the class's prototype.
 // can be called with another class, or a plain object hash containing new members.
 Class.mixin = function(members) {
-	copyOwnProps(members.prototype || members, this.prototype);
+	copyOwnProps(members.prototype || members, this.prototype); // TODO: copyNativeMethods?
 };

src/common/Grid.js

@@ -510,7 +510,7 @@ var Grid = fc.Grid = RowRenderer.extend({
 
 
 	// Renders a set of rectangles over the given segments of time.
-	// Returns a subset of segs, the segs that were actually rendered.
+	// MUST RETURN a subset of segs, the segs that were actually rendered.
 	// Responsible for populating this.elsByFill. TODO: better API for expressing this requirement
 	renderFill: function(type, segs) {
 		// subclasses must implement