Bugfix pagination_bar to work with only one param/value pair.
A valid test of this patch is this command:
perl -MC4::Output -e 'print pagination_bar("my/script?query=foobar",5,2,"page"),"\n";'
The output before patch begins:
<a href="my/script?query=foobar?page=1" rel="start"><<</a>
and AFTER patch:
<a href="my/script?query=foobar&page=1" rel="start"><<</a>