Import skinlf-1.2.3-20020729 as wip/skinlf.

This is SkinLF (Skin Look And Feel) version 1.2.3.
SkinLF allows Java developers to write skinnable applications using
the Swing toolkit.

SkinLF currently supports skin files created for GTK and KDE.
Only image themes are supported (engine image).

The official web site is:
        http://www.L2FProd.com/software/skinlf/index.html
Install into a separate prefix to avoid conflict with guile-1.8.x.
Change PKGNAME to guile20 for the same reason.
Adapt buildlink3.mk file so it is found and works correctly.
Remove guile2, now lang/guile20.