Don't die on trailing whitespace in a connection string

Currently, if you give pq a connection string with a trailing
whitespace, pq likes to die with the confusing message pq: invalid
option: ""

This patch just trims whitespace around the connection string so that
when parseOptions splits on " ", it doesn't get a spurious empty
option.

Editorialized by Daniel Farina <daniel@fdr.io>
Add contributor: Bill Mill
Add more accurate copyright clause

Many people have contributed anad I've made effort to track every one
in README, and their copyrights apply to this work.  So, I don't think
ths change does anything but reflect reality.