Bugfix: Don't produce error in simplify_program/2 when there are no user-defined program/1 instances.

Only translate an action to PDDL if it does not mention any non-CWA properties in effect conditions.

Use '_' instead of '-' in room names of Wumpus world due to better compatibility with PDDL planning.

Coordinates in Wumpus world are numbers, not standard names, hence not a type according to logic/cwa.pl.

Compile away conditional effects on action costs function when translating to PDDL due to lack of support by planner.

Updated README to reflect usage of most recent versions of NuSMV model checker and Konclude description logic reasoner.

Optimization: Only consider fluents mentioned in the characteristic set whose instantiated SSA is non-valid for local-effect progression.