This class works just like LWP::UserAgent (and is based on it, by being a
subclass of it), except that when you use it to get a web page but run into a
possibly-temporary error (like a DNS lookup timeout), it'll wait a few seconds
and retry a few times.

It also adds some methods for controlling exactly what errors are considered
retry-worthy and how many times to wait and for how many seconds, but normally
you needn't bother about these, as the default settings are relatively sane.
