Introduced a new log verbosity level, so now DEBUG is really for debugging. Refactored a bit maxmemory. When virtual memory is short in RAM free the objects freelist as well as swapping things out.

New object field (one of the unused bytes) to hold the type of the swapped out value object in key objects

rdbLoadObject() as a separated function to load objects from disk. Dropped support for RDB version 0, I guess no longer has this legacy DBs around

saving code refactored a bit, added a function returning the number of bytes an object will use on disk

Fixed a minor bug in GETSET, now the SET part is not performed if the GET fails because the key does not contain a string value