Release 0.56.0

[Marc Worrell]

Hi,

We have released Zotonic version 0.56.0.

This is a maintenance release that focuses on stability, code

cleanups and tracing of slow database queries.

Possible breaking changes:

 * We removed jquery-migrate from the standard template in
   ``modules/mod_base/templates/_js_include_jquery.tpl``.
   If you need jquery migrate in your project then you can add
   this template to your site and re-add ``"js/apps/jquery-migrate-1.4.1.min.js"``
   to the include library files.
 * The ``{% image %}`` tag now includes ``width`` and ``height`` attributes.
   Ensure that you have width or height set to *auto* in your css if you are
   restricting one of the dimensions. Otherwise use the new ``nowh`` option
   to the image tag to suppress the width/height attributes.

Main changes are:

 * Added tracing of database queries - switch on at the /admin/development
   and see SQL traces (and explain of slow queries) for your session only
   in the console log.
 * Removed jquery-migrate from the standard jquery include
 * Image tags now include width/height attributes
 * Language preference is now stored in ``z.lang`` cookie instead of the
   database persistent storage. This greatly reduces the number of rows
   being added to the persistent storage table.
 * SQL queries that timeout are now canceled, the query is now also
   monitored and logged in case of crashes or timeouts.
 * If an email is received for an unknown hostname then a temporary
   error is returned if and only if there are enabled sites that are not
   running.
 * Transport retransmission is now disabled. This turned out to cause
   more problems than solve, due to duplicate requests being sent in case
   of slow servers, making the server even slower.
 * Pivot queue inserts are now more robust and handled by the pivot
   server process, this prevents race conditions.
 * The site supervisor is reorganized for greater robustness against
   crashing of some services. These services are now organized in their
   own one-for-one supervisor and are independently restarted.
 * Next/prev on the admin edit page is now evaluated when clicked. This
   keeps the correct category and speeds up page load of the edit page.
 * Long connection lists on the admin/edit page are now truncated and
   can be viewed in full on the connections page.
 * File modification times are now cached, this speeds up the template
   modification checks on busy servers.

See the full release notes at:

http://docs.zotonic.com/en/latest/developer-guide/releasenotes/rel_0.56.0.html

Kind regards,

The Zotonic Team.