Make columns an ordered dict so that collection tables work properly with elasticsearch backend.
make it possible to have an unindexed array property by specifying items: {}
add page schema, two page collections (about and help), and a couple test about pages
add components for rendering page layout
improvements to page layouts

* make the layout an object with rows as a property
* render bootstrap column classes based on column count
* dispatch block rendering based on block type, with a fallback that uses the Panel component to show JSON
* richtext block view