[plt-scheme] Planet Updates: Scheme, FastTest, and Dracula

I have just updated my planet package cce/scheme to version 6:0.  None
of the functionality has changed, but some of the bindings have been
moved between libraries.  Also, the package is now compatible with PLT
Scheme versions 4.2+ (improved from 4.2.1 through 4.2.1.x).

The primary change is the separation of (planet cce/scheme/scribble)
from (planet cce/scheme) and (planet cce/scheme/planet).  Now only
code that explicitly requires (planet cce/scheme/scribble) will depend
on the Scribble back-end, which makes sandboxed evaluation of code
using (planet cce/scheme) easier.  The Scribble back-end performs some
file system checks at start-up that can trigger sandbox security
guards.  The end result is that users building Scribble documentation
with the */this-package bindings must now require (planet
cce/scheme/scribble) directly.  Most other uses of the package should
be unchanged.

I have also updated FastTest and Dracula (to versions 3:6 and 8:4
respectively); they now use the new version of cce/scheme and are
compatible with PLT Scheme versions 4.2+ as well.  None of their
functionality or interfaces have changed.

Carl Eastlund