One might not expect to get a URL with params separated by & while
this is the correct way of writing them to HTML attributes. So default
behaviour is right now that all functions return URL params separated
by &, but if you cast a URL (or it's params) to a string, & will be
used.
Additionally there are toString functions allowing you to choose the
separator "manually".
refs #6699
The URL query string parsing done by PHP/ZF doesn't suffice our needs.
This is an implementation preserving filter-related "strange" query
string components while still offering legacy behaviour.
Missing right now: support for [].