Add tests for checking docs against each other
Add the ability to check docs against each other
Add Test::Tester as a test dependency
Add extra check that a node's parent is correct
Actually implement the parent check
Build the expected doc manually in image link test
Add some more elements to element_classes
Make sure image elements have parents
Make Link->link read-write
Make Link->link set once
Add MooseX::SetOnce as a dependency