[BRLTTY] Copying over terminal boundaries

[Teemu M Kuusisto]

Hello

My console's height is 64 lines and width is 128 characters. The simplest 
way to copy a couple of lines is to mark the 
begin position to leftmost character in the first line and then place 
the end position somewhere out of the real terminal in the last 
line (character position > 128). That was possible with an older BRLTTY 
version, but with 4.0 it is 
not allowed any more. The result of this change is that I have to place 
the end position exactly to the 128th character when I want lines to be copied
completely - not so easy way.

-Teemu