[Simh] Card reader support in TOPS-10

[bsupnik at comcast.net]

After reading CD2SER.MAC, it's fairly clear that TOPS-10 only supports the CD11, not the CR11.  Thus, pdp11_cr.c needs rather more extensive work than I thought, so that it defaults to a CD11 on the PDP-10, and it's not possible to set CR11 mode.  Further, VMS only supports the CR11, so modifications are needed to prevent setting CD11 mode on the VAX.

I'll get around to this when I can.

/Bob