[ros-svn] [ion] 20780: - Fix MmCreateKernelStack to actually take into account the GuiStack parameter.

[ion at svn.reactos.org]

- Fix MmCreateKernelStack to actually take into account the GuiStack parameter.
- Implement KeSwitchKernelStack
- Enable code in PsConvertToGuiThread to create a new stack and switch to it. GUI Threads now get the 60KB of kernel stack space they deserve.
- Define exported DDK constants for kernel stack size and undefine our own internal ones.


Updated files:
trunk/reactos/ntoskrnl/include/internal/ntoskrnl.h
trunk/reactos/ntoskrnl/ke/i386/usercall_asm.S
trunk/reactos/ntoskrnl/mm/process.c
trunk/reactos/ntoskrnl/ps/win32.c
trunk/reactos/w32api/include/ddk/winddk.h