[sldev] [svn] good-bye windlight, hello maint-render-2

[Soft]

windlight is officially in the mainstream release candidate. There
will be no more windlight drops. Instead, look to the maint-viewer-2
branch in svn for incremental rendering fixes. That should drop in the
next hour or so.

Also, I'm gradually transitioning the external repositories in
"branches" to match the internal repository names, which usually
include a numeric suffix that's incremented when rebranching from
"release" (rightly "trunk"). With these, you can use svn log to look
at only the differences from release. Normally the first two commits
will be for synchronizing against release, and subsequent commits are
development exclusive to that branch.

I'll follow up with messages when a branch is deprecated in favor of
another so you know to perform an svn switch.