Apache Forrest code remove (bug FOR-181)

code remove
by
DB
(fixes bug FOR-181)

:

Skins "forrest-css" and "avalon-tigris" are deleted. The
"tigris-style" is renamed to "tigris". Aliases
set in place for backward-compatibility.
The old "forrest-site" and "krysalis-site" skins are retained for
a little while longer,
but are deprecated, so please move to one of the other skins.
See notes about Default skins.