Update to a more recent version of md5.lisp, taken from SBCL's SB-MD5
contrib. The change is motivated by the fact that SBCL generates a runtime
error "function declared not to return returned" with the current
code. Made a few changes to make the code compile in other Common Lisp
implementations.

darcs-hash:c434dc3b54088edf030c3909c5f03080c396f9d4

- export the *PG-CLIENT-ENCODING* variable from the PG package

darcs-hash:0d6a4c5adf520d8d58b73ffb79ee6b0e2a961fe1

untested COPY IN/OUT code. I am not happy about how this looks...

darcs-hash:fc7216ed2ec2b21ce7f151b922ce2b133d3c9c76

added pbe functions

darcs-hash:775e1869223ebed940630044c72f10421485bb45

initial import

darcs-hash:3eba5477bf5e3b095b88e97e474746b61304a343