- 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

# example: message box on windows

h <- rdcLoad("user32")
f <- rdcFind(h,"MessageBoxA")
rdcCall(f,"ippi)v",0,"hallo","welt",0)
rdcFree(h)