changed the names of all mixins to Mixin-able to represent interface concept.
autoScrollable encapsulates all the necessary functionality for iscroll scollers.
If a new scroller needs to be used, create a new mixin that satisfies the protocol.
Using data-*** or, mixin based determination of whether the page is scrollable need to be determined. Think about it.

Added events and expressions to Ext classes. Need to revisit them and how to represent.