Parallel set of flag bit definitions: SFX_FILTER_FOO and FLAGVAL_FOO

[Tor Lillqvist]

Caolán pointed me to this email from 2006 that describes the meaning
of most of these flag bits:

http://www.mail-archive.com/dev@openoffice.org/msg05047.html

I pasted that description into a comment in the documentconstants.hxx file.

In 4.0, if not earlier, we should drop the parallel set of names for
these bits, and rename some to have more descriptive names. It sounds
a bit schizophrenic that something can be both "own" and "alien" at
the same time, and even "3rd-party" too)

--tml