<span typeof="mw:Entity"> tags are now correctly represented in the
model, and rendered in CE. There are still issues with cursor movement
etc. in CE.
Because the prioritization mechanism for annotations vs nodes is broken
in the current "node API", I had to hack two special cases for mw:Entity
into the converter. I also had to change the converter to ignore the
children of inline nodes (this was a legitimate bug, but had never come
up before).
Change-Id: Ib9f70437c58b4ca06aa09f7272bf51d9c41b18f2