added enyo.Table

enyo needs a simple, yet powerful table kind. This kind can be used by simply passing an array of row arrays to 'rows'. You can instead pass an array of arbitrary objects, each corresponding to a row. then define a mapping of what goes into which column with the `columns` array. Finally, a column could be defined by a function that is passed the rows arrays. This can be used to perform calculations on data, or transform it for display. Please see my corresponding onyx pull for a sample application.