surrounding a device tile may cause the device to be extracted
with the wrong node (picking up the node from the wrong side of
the diagonal tile). Added extra handling to capture the case
where two ports on two different nets are merged when using
"ext2spice short" (previously it was handling only ports on the
same net). Also: Removed the redundant readline-4.3 from the
readline/ directory; only readline/readline is left, which is
version 4.3.