Make simx86 more functional with DPMI code (both native and emulated).
Adjusted bogus ((int)_cr2 < 0) test. Signal handlers use the signal stack
and perhaps queue, and restore eflags, fs and gs. Revert the meanings of
config.cpuemu==2 and 3. The fault handler takes better care of VGAEMU.


git-svn-id: https://dosemu.svn.sourceforge.net/svnroot/dosemu/trunk@1225 7758b857-130e-0410-ab9c-d8735a528d18