* module/ice-9/safe-r5rs.scm: Define local versions of `case' and `cond'
that assume aux syntax is unbound. If this doesn't work, we can
switch to exporting aux syntax.
* module/ice-9/top-repl.scm (top-repl): Don't add (ice-9 r5rs) to the
REPL environment.
Moved ice-9/ and oop/ under module/, with the idea being that we have
only scheme under module/. Adjusted configure.in and Makefile.am
appropriately. Put oop/ at the end of the compilation order.