Layout updates.

Support for custom layout controllers, along with a BorderLayout controller which uses a dijit/BorderContainer.  Changed data-app-region to data-app-constraint, and added config support to set the constraint for a view in the config.  Also added support for multiple views in the defaultView, the views should have different constraints and are separated with a +.
The + can also be used for multiple selected views in a transition or a url.  Last change was to rename the events used by Layout, the change was to make layout->initLayout and select-layoutView, and I added an event for resize which will be called by transition after layoutView is called for the last view being transitioned to.