Tweaked Pjax API docs to inlcude @since tags.

Removed unused var in pjax.js.

Makes sure the "pjax=1" query param is inserted before any hash.

Removed trailing comma from pjax.js which prevented IE6 from parsing it.

Comment tweak.

Comment fix.

Add an `addPjaxParam` attr to work around browser cache collisions. When true (the default), Pjax will add a "pjax=1" param to the URL to ensure that Pjax responses are cached separately from full page responses.

Add a `url` property to the event facade of 'load' and 'error' events.

Pjax API docs.

Rename Controller to Router. Y.Controller is now an alias for Y.Router (ditto the controller module), but this alias will be removed in a future version of YUI.

Update Pjax to deal with Controller changes.

Moved content related methods and attributes from PjaxBase to Pjax. PjaxBase does not use `getContent()`, `contentSelector`, or `titleSelector` internally; it makes more sense for these content related methods and attributes to live on Pjax.

Refactor Pjax into pjax-base, pjax, and pjax-plugin modules. PjaxBase is meant to be a mixin for Controller. Pjax extends Controller and mixes in PjaxBase to provide a usable Pjax implementation. Plugin.Pjax extends Pjax and can be plugged into a Node instance.

Remove unnecessary event publications.

Split pjax into "pjax" and "pjax-plugin" modules. Y.Pjax has all the functionality, but isn't a Node plugin so it doesn't actually do anything with Ajax responses. Y.Plugin.Pjax injects the response content into the host node and updates the page title.

Make `linkSelector` initOnly and add more tests.

Pjax tests. Mostly there, but still a few more to write.

Early (untested!) work in progress on a pjax plugin for Y.Node.