new x-meta protocol, begin distributing metadata.html
untabify
initialize `crumbs` property to an object so it can be initialized via JSON in markup
default to showing page 0
use noscript
make no-theme result 'null' insetad of 'undefined' to avoid spurious data changes (i.e. observation of value going from null to undefined)
add 'basic-app' experimental element(s)