By default the API inhibits empty queries and fragments extracted.
Unless this new flag is set.
This also makes the behavior more consistent: without it set, zero
length queries and fragments are considered not present in the URL. With
the flag set, they are returned as a zero length strings if they were in
fact present in the URL.
This applies when extracting the individual query and fragment
components and for the full URL.
Closes#13396
The threee tags `<name>`, `</name>` and `<command>` were frequently used
with a leading space that this removes. The reason this habbit is so
widespread in testcases is probably that they have been copy and pasted.
Hence, fixing them all now might curb this practice from now on.
Closes#12028
Fixed some issues that caused xmllint failures, added features
and keywords, fixed some quotes and removed some <strip> sections
that unnecessarily limited test checking.
