renaming Net/ThemeName to Gtk/ThemeName and Qt/ThemeName

[Akira TAGOH]

Hi,

I suppose that the concept of this design is great though, the fact is
most theme is provided only for either of toolkits and can't share the
value on Net/ThemeName in XSETTINGS registry. this often causes a
trouble to run applications on different desktop, such as GTK+
applications on KDE and Qt applications on GNOME. so IMHO that would
reasonably be better to have separate registry for each toolkits and
obsolete Net/ThemeName. or the toolkit specific registry as the
fallback and keep Net/ThemeName for primary registry.

Any thoughts?
-- 
Akira TAGOH