Some overview docs. on symbol problems

    The overall strategy with bullets / symbols is this:

    1. user creates a bullet with a font that exists eg. opensymbol.
    2. on save to MS format map known symbols to the "symbol"
       font for maximum interoperability
    3. on load keep the "symbol" font associated with bullets (which
       causes the selector to behave strangely), and map this back
       to opensymbol each time we render to the screen.

    In addition to this, there is a special 'Symbol' textencoding
which differs per symbol font, but provides an extra piece of markup
information. The code involved in these stages is:

* Mapping on MS export

    sw/filter/source/ww8/wrtw8num.cxx (SubstituteBullet):
	calls CreateStarSymbolToMSMultiFont
    vcl/source/gdi/fontcvt.cxx (StarSymbolToMSMultiFont) class
	this does various splitting / mapping stuff for export.

* Mapping on render

    vcl/source/gdi/fontcvt.cxx (ImplRecodeString)
	the outdev3.cxx font engine decides which font to map eg.
	"symbol" to, and then calls ImplGetRecodeData, which builds
	an ImplCvtChar structure, containing pointers to character
	re-location tables for that font mapping.

* Symbol textencoding

    cf. RTL_TEXTENCONDING_SYMBOL and code in sal/textenc.