pangowin32: Read the font fallback list from the registry instead of hardcoding it for some fonts.
We only had a fallback list for "Segoe UI" which is the default Windows font, but not on Chinese or Korean Windows version which use "JhengHei UI" etc. and fall back to "Segoe UI".
Instead of hardcoding the fallbacks in the alias list read them from the registry (HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows NT\CurrentVersion\FontLink\SystemLink)
This should allow us to use the default Windows font by default in gtk+ on Win8+, see gtk!436 (merged) for details.