licenses: add Sleepycat Public License

Signed-off-by: Austin Seipp <aseipp@pobox.com>
ike: use stdenv.lib.licenses.sleepycat

Signed-off-by: Austin Seipp <aseipp@pobox.com>
db: Berkely DB (was) licensed under Sleepycat by default

6.0 and newer are still under AGPLv3 however.

Signed-off-by: Austin Seipp <aseipp@pobox.com>
mps: version 1.113.0

Signed-off-by: Austin Seipp <aseipp@pobox.com>
Merge branch 'mps' of git://github.com/thoughtpolice/nixpkgs

Add mps 1.113.0, fix usage of Sleepycat license