System processes are now killed only after the server persistence
delay has expired. New processes are not allowed to start during
shutdown.

server: Add support for system processes, that can be signaled to exit when all non-system processes are done.

With help from Ken Thomases.

Make it an unsigned int to save some space on Win64, if we need to
transfer more than 4Gb over the server pipe something is seriously
wrong.

Pass the socket for the new process from the parent through the
environment.
Perform initialisations during the new_process request.

in an active process, instead of sending a SIGTRAP.

the process parameters structure in ntdll instead of kernel.

instead of waiting for the init_process request.

request to get_startup_info.

desktop, not from the parent thread.
Fixed a couple of bugs in the desktop name handling.

- adapted accordingly kernel32 atom support

GetClassWord/Long (based on a patch by Mike McCormack).
Various fixes to the class instance handling.

attached to or detached from a process.
Don't send exception events to the server unless a debugger is
present.

- Added handle information to (wineserver) process snapshot.