Possible improvements:
-Investigate the problem of bogus dots that stay on when they should
   be cleared. Currently we double all display update commands. Is this
   only on older Voyager hardware? Is this only on Linux?
-Investigate the frequent USB stall errors. We had to implement a
   retransmission system. Again, is this only on old Voyager hardware,
   and is this problem occuring only under Linux?
-Investigate why setting the voltage and then getting back the voltage
   value yields apparently inconsistent results.
-Test on RedHat stock kernels.
-The command to shut off the display is effective when you press ctrl-C
   from vgertest, but not when you kill BRLTTY. Why?
-Official minor assignment.
