Cleanups internal database.
Usage:traverse_clauses(Cls,Ds,Flag,NewCls,NewDs)
It traverses program clauses Cls suitably changing the format for the following step (analysis, annotation, etc). In general, it will have to remove disjunctions, if-then-elses, nested CGEs, etc. The particular format is indicated by Flag. In doing this, the old clauses will be transformed and new clauses (and thus new dictionaries) can be created.