Store cached string length in StringAtom, plus some cosmetic stuff
Added missing copy constructors and copy-assignment operators to Ptr
New global constants EndOfString and EndOfStream
Added new min/max grow defines for streams
Added StringAtom::Length() to test
New module Messaging, only a universal serializer class for now
Cmake file update for Messaging module
Stream/MemoryStream fixes, StreamReaders and StreamWriters, plus tests