- further fixes of inccorect overflow errors for int (and long on LLP64 systems) * prev commit had bugs * added overflow tests for also int, long, long long (for both, lp64 and llp64) - while at it, fixing a reference leak when not using python with utf8 caching

win32   demonstrates a win32 message box
darwin  demonstrates a darwin specific example
w32PlaySound	PlaySound on Win32 using dyn.load facility
linux   demonstrates a linux specific example