Deprecations in Enyo 2.4

[Ben Combee]

We're working on preparing for a 2.4.0 release soon, and part of that is deprecating some parts of 2.3.0 that we don't want to support going forward.

The first is enyo.GridList (in the layout repo) and it's derivative moon.GridList.  This code has been superseded by enyo.DataGridList and had known performance and usability issues, so we're going to take them out of their package.js files, while leaving them in the tree for a release if you need to manually use them.

The second is the filter mechanism in enyo.Collection.  The filter() method will still be around to provide a filtered set of items in the collection, but the whole filters and activeFilter mechanism is being removed, as it's being replaced by a new mechanism in development for a post-2.4 release.  Since the mechanism are going to clash, we want to remove this now before it gets wide use.

Anything else that you think feels crusty in Enyo that we should consider removing now? 

One change that I'm personally thinking about is renaming enyo.union which doesn't actually perform the standard union operator, instead doing more of a union - intersection operation, but don't want to break any code that could be using that already.