extdirect 0.4 released: Batched requests, new licensing

Sorry it's taken so long, those of you who've made requests and opened tickets, but finally, there's an update to extdirect. This release adds support for batched requests as described in the Ext.Direct spec (multiple calls within a certain amount of time are gathered into a single request).

In addition, I've removed the actual ExtJS code itself so this could be released under a less restrictive license. Ext 3.x is now merely a prerequisite.

Thanks to Brian Edwards and Jon-Pierre Gentil for their work on the analogous code in Zenoss, a version of which made its way into this release.