Also, add insert and find buffers to the header, making it 3 lines
high.
Also, fix the "I" overshadowing word which wasn't operating on the
proper RSP level.
Also, fix I which didn't mark the block as dirty.
Also, made LIST properly handle full 64-chars lines not ending with
a null or CR. Previously, such a line would be accompanied by its
following line, duplicating that line's output.