Fixed bug in (concepts :next-closure ctx)
Fixed bug in (concepts :next-closure ctx)

and made it a little bit faster.

Signed-off-by: Daniel Borchmann <25857343a15bf1edafebc2912e82ecf775c585c1@mailbox.tu-dresden.de>

Lobage/conexp-clj,exot/conexp-clj,exot/conexp-clj,exot/conexp-clj,fcatools/conexp-clj,immo/clojure-conexp,fcatools/conexp-clj,fcatools/conexp-clj,Lobage/conexp-clj,Lobage/conexp-clj,fcatools/conexp-clj,Lobage/conexp-clj,immo/clojure-conexp,exot/conexp-clj,exot/conexp-clj,fcatools/conexp-clj