Convert the legalizer/boundary module to FuncCursor.
Convert the legalizer/boundary module to FuncCursor.

This is a larger refactoring because all the changes need to be done
together. Either you pass a Function reference around, or you pass
around references to the parts. There is no in between.

sunfishcode/cretonne,sunfishcode/cretonne,stoklund/cretonne,stoklund/cretonne,sunfishcode/cretonne,stoklund/cretonne