Bring PostgreSQL functions closer to the current level of PL/pgSQL: - upgrade PL/pgSQL functions to the $$ notation (recommended since pg8.0, jan 2005). - get rid of backslash usages in function definitions - drop aliases in favor of named function arguments (recommended since pg8.0) - fix wrong function_args, add missing function_args, align default semantics with the defaults in pg (providing "null" as default means the argument is optional). - change return types of triggers from "opaque" to "trigger" (recommended since pg8.0) - unify names of triggers *_tr - removed some version dependencies of pg 7.2 and 7.3