Constants whose values can be assigned via the command line

[rtaupe]

It would be nice if Alpha supported constants whose values are assigned via the command line (as does clingo). Then, we could write programs like the following: time(0..maxtime). The value of maxtime could be passed from the outside: java -jar Alpha.jar -c maxtime=100

Currently, we have to use programs like the following: time(0..T) :- maxtime(T). Then the value for maxtime is included in the problem instance: maxtime(100). Technically, this even makes it necessary to forbid the existence of two different values: :- maxtime(T1), maxtime(T2), T1<T2.