[CSRSRV]: Port CsrCallServerFromServer (and hackplement a reactos-compatible implemem...

[CSRSRV]: Port CsrCallServerFromServer (and hackplement a reactos-compatible implememntation) from CSRSRV2.
[CSRSRV/CSRSRV2]: Fix CsrLockProcessByPid -- it was skipping the root process itself, so requests coming from a CSRSS-hosted DLL would fail (which is exactly what server-to-server depends on).
[NTDLL]: Enable support for server-to-server calls!
Server-to-server calls work now, and one of the multiple mapping hacks is gone. User32 and kernel32 still need a bit of fixes to get rid of the other hacks, though. Also, Perf++.

svn path=/trunk/; revision=55677