Unix CLI option to set windowtype

Unix CLI option to set windowtype
Add the ability to select the windowtype on the command line on Unix using
a new -wwindowtype option.  I had thought the proposed patch could core
dump, but the default windowtype selection occurs earlier and ensures
that raw_print will always work.  So, the only problem with the proposed
patch was it didn't move the linux and sco special-case code until after
the selection was made.  That special-case code really should be moved to
to wintty.c, IMO since it doesn't affect other windowtypes.