Now the `'*'` characters in fixed-width blocks show up correctly,
with respect to how I write code. (I think doxygen also swallows
them anyhow, so the highlighting is more consistent with doxygen's
parser.)
Also on loading a file, everything looks better now.
I made `cpp.cplusplus` a hybrid filetype which tricks the vim
highlighting into believing that we're really in raw C++ for the
purposes of the core vim highlighting rules. My `cplusplus` type
adds more bits to the core stuff, but mostly exists to let
doxygen slip in the way that I want it to.
This "cplusplus" filetype permits the sourcing of `cpp.vim`
and `doxygen.vim` as lower-level files from itself. This should
permit `doxygen.vim` to source from `cpp.vim` and avoid endless
recursion, when handling code-in-comments formatting.
