add *-count of *-list elements

This adds *-count for every *-list element
on the same level if available as attribute.

Example:
<release-list count="42">
  <release>...</release>
  ...
</release-list>

->

{"release-count": "42",
 "release-list": [...]}

Signed-off-by: Johannes Dewender <github@JonnyJD.net>
update docs and examples for *-count

Using *-count should be optional,
since this isn't available in earlier musicbrainzngs releases.

Signed-off-by: Johannes Dewender <github@JonnyJD.net>
Merge remote-tracking branch 'jonnyjd/list_count'

Signed-off-by: Alastair Porter <alastair@porter.net.nz>
convert query parameters to a list before encoding

Unlike a dictionary a list has a known ordering, so we can
always expect the resulting parameters to be in the same order
between different python versions for testing purposes.

Signed-off-by: Alastair Porter <alastair@porter.net.nz>
convert list counts to numbers

Signed-off-by: Alastair Porter <alastair@porter.net.nz>