t/pptest.t - change $ to $^W (line 69)

This avoids "control character" deprecation warning with 5.20.0.
ord '' and ord 'ctrl-W' (^W) are both 23 - which I presume is
connected to the creation of the problem.
Strip newline from last COLIDS string, sf.net bug #362

We were already stripping the newlines from the data
lines but missed adding this to the COLIDS handling.
Thanks to aero for reporting and ZM for submitting the
bug ticket.
Fix sf.net bug #360 to handle integer overflow

See the sf.net ticket for information on the problem for vsearch
where an integer overflow will result in incorrect answer being
returned.