Zone Changelog: filter and paginate

[uedvt359]

Most of what I'd consider controversial takes place in models/zone.php:list_changesets():

• It now takes an optional parameter for a list of filters (search comment, date range, pagination)
• It now returns two values (changes as before, plus total number of pages) => this is a breaking (internal) change, so all usages were updated.
• Items per page is for now hardcoded in there to 200. I'm open to improve this (config.ini knob?) if this is a problem.
• The SQL statement to select changelog entries is now relatively complex. To allow for the optional filter parameters, they have to be passed twice. This is a bit ugly, but I don't see a nicer alternative (assembling the SQL query as a string with if/else seems even worse).

I'm also a bit unhappy with the amount of <?php...?> blocks for pagination in templates/zone.php but there's just a lot of cases to check.

commit message:

Implements:

• filter by comment (default all)
• filter by date range (default all)
• paginate results (200 items per page)

Filtering by author, while possible, is not implemented in this patch, since we don't care about it. Note that the changelog displayed on a user's profile is not touched; it continues to be unpaginated and unfilterable for the same reason.

fixes #179

[uedvt359]

I hope this doesn't come across as pushy, but do you have the time to review this please, @thomas-pike?

[thomas-pike]

I hope this doesn't come across as pushy

Not at all, thanks for reminding me to look at this. I'll take a look now.

[thomas-pike]

Thank you for your continued contributions!