add conexp.fca.graph with graph<->lattice conversions and (co)comparability
add conexp.fca.graph with graph<->lattice conversions and (co)comparability

fcatools/conexp-clj,fcatools/conexp-clj,exot/conexp-clj,fcatools/conexp-clj,exot/conexp-clj,fcatools/conexp-clj,exot/conexp-clj,fcatools/conexp-clj,exot/conexp-clj,exot/conexp-clj