rpcrt4: Raise an exception if a NULL ref-pointer is passed in to PointerMarshall or PointerBufferSize.

The World SID now maps to user|group|other instead of just other.

This caused only the first ACE to be examined, causing permissions to 
always be set to ----???---.

server: Change the get_dll_info server request to allow retrieving the image file name of a process.

Implement NtQueryInformationProcess(ProcessImageFileName).