Change build tool from Ant to Grunt.
Fix Ajax proxy's `urlAppend()` method to handle the special case of the url having a '?' at the end of the string. No separator character is appended in this case.
Change Ajax proxy's `buildUrl()` implementation to always add the `pageSizeParam` if it is configured, and there is a value for it.
Refactor Model's `set()` method to split out its actual setting functionality from its Object parameter processing functionality. Created new method, `doSet()`.
Add `ignoreUnknownAttrs` config to data.Model, and `ignoreUnknownAttrs` option to its `set()` method.