#130 Extend error information in case of failed dispatch call

[Stefan Schukat]

COM objects which implement IDispatch return error information via excepinfo during an Invoke call if the dispatch call fails with DISP_E_EXCEPTION. In case of other error codes extended is not available. This patch checks if the COM object supports extended error information via the IErrorInfo interface and transforms it to an EXCEPINFO structure to provide the caller with extended error information via the standard way.

[Mark Hammond]

Sorry for the delay, but better late than never :) I checked in a slightly modified version as 4391:fac37b1e89a7 - thanks!