[SETUP][SYSSETUP]: Export a 'InstallWindowsNt' function from syssetup.dll (with Windows-compatible signature) instead of our private 'InstallReactOS' and 'InstallLiveCD', and call it from setup.exe. This allows using our setup.exe on Windows & vice-versa for testing purposes. In syssetup.dll, the choice of installing ReactOS or starting the LiveCD interface is done by checking the command-line given to 'InstallWindowsNt' (using the existing switches).
Inspired from Jared's patch in CORE-12615.
svn path=/trunk/; revision=73519