I was particularly suprised by the conditions that checked if
`$parser->extCite !== $this`. This can never happen. Maybe it was
possible in a very old version of this code, but it is not any more.
Change-Id: I049ff4109a747eb9dbf325c24cf20f65753827dd
As of now, this patch does not touch the existing code. However, the
goal is to remove a lot of the related code from the Cite class. This
will be done in later patches. This here is a separate patch to make
reviewing the later patches much easier.
The existing parser tests should be proof enough this chain of patches
is not changing any behavior.
Change-Id: I27ae972f81071bb4036bd452560768fae409417b