Add an option to set list order by default - admin list of articles

![default_ordering_button](https://f.cloud.github.com/assets/2385058/1916263/f48fb526-7d74-11e3-94bf-2fc65b61e9bb.png)

A button to save the current list ordering as default in admin.
This button sets this ordering for all users with access to admin, and is only visible to users with core.admin permission (access to options).
The settings are saved in params (hidden fields in config file)
Currently, only added in com_content, but could be added in other lists (users, categories, and every list of Joomla).
Advice, comments or help from contributors are welcome!

Request Issue: [#33108] Add an option to set list order by default - admin list
link: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=33108&start=625