list.inc: PGPList: enhance get() to include object type to return, PGPList:...

list.inc: PGPList: enhance get() to include object type to return, PGPList: enhance searchCallback() to include search direction and starting node for search, PGPList: add searchAll() to return list of items meeting search criteria; object.inc: PGPBase: enhance search() to include object type to return and search direction, PGPBase: refactor searchForward() and searchBackward() to call search(), PGPBase: enhance searchCallback() to include search direction, PGPBase: add searchAll() to return list of items meeting search criteria, PGPClass: add getParameterVariable() to strip any default value assignment or inline comments, PGPFunctionCall: enhance stripComments() to create new object instead of cloning, PGPFunctionCall: refactor searchForward() and searchBackward() to call PGPList::search(), PGPAssignment: add getValue() to return the assignment value, PGPArray: add traverse2() to invoke callback on array elements; parser.inc: rename error handler variable; reader.inc: update documentation.