Make permissions defaults consistent and documented.
Remove any state freeze from PageBuilder
Rename ContainerBuilder.build*() methods
Add Container.build()
Let buildToTopBuilder() and buildToParentBuilder() do only what follows
from their names
Make Container.build(), buildToTopBuilder() and buildToParentBuilder()
callable multiple times safely
Make Container.buildToTopBuilder() able to climb up the parent container
builder hierarchy and only add the ultimate parent builder to the page
thus being a shorthand for closing all parent builders.