Golog: Nondet/Alt are binary instead of lists, renamed some constructs.

* Nondet and Alt both take two arguments instead of a list of arguments.
* Renamed some constructs, e.g., Atom -> Act, PseudoAtom -> Atom.
  These are only cosmetic changes. I'm not sure whether they really make
  sense.
Golog: renamed Nondet to Choice, nondet to choice.
Golog: renamed star to iter. Replaced maximumBy by new maxBy.