win32 native aufs

Well,
    I've implemented pthread_cond* in cygwin (available in the 1.3.0
code - CVS HEAD branch), so the native win32 threaded code is no longer
needed. The in-cygwin implementation runs the existing aufs code nearly
unaltered. The attached patch brings in the same file mode details
already implemented in ufs for cygwin (O_BINARY), not unlinking open
files... and #if tests the scheduler settings which aren't present on
cygwin yet.

Rob