convert to using stdio to line buffer usb output... This reduces
usb traffic like when doing hexdump...

The delay works, but could be a problem on slower systems...  It's
been reported, so hopefully a fix will happen..

The old method would introduce a race condition where the buffer
could be overwritten before the data was consumed.  For slow, single
character typing this was fine, but w/ packets being generated by
a computer, this would cause corruption of the incoming data..