Cpsvar: separates recursive and non-recursive occurrences
Cpsprint: change printed representation of continuations
Cpsvar: correct typo
Cpsdef: update doc and interface to handle recursive occurrences.
Cpsvar: update comments
Cpschange: Handle rename of occurrence_number -> number_of_occurrences
Cpschange: some arguments now take a occur_maker instead of a var
Cpsbuild: now uses the occur_maker
Cpsbase: handle recursive occurrences