Make preview possible if session_enabled = 0
Another version of improved widget of active users

This is the new commit for issue #11107
Now it uses subquery with nested sorting and must work on any type of database.

I have table with 45000 records and when I select last actions for 50 hours this query takes only 0.0287 sec.
tmp
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First step to content type headers
Slight cleanup
Some more cleanup
Support custom http headers on content type creation
Improved groupbe

According to http://dev.mysql.com/doc/refman/5.0/en/group-by-extensions.html
Update widget.grid-online.php
Check for additional valid MIME types for zip files.

Wondered why my local transport packages aren't valid zip-files for MODx until I found out that Firefox is uploading them with MIME type 'application/x-zip-compressed'.
Bugfix in package name validation code

According to the docs (http://php.net/preg_match) preg_match() only returns a boolean false, when an error occurs, but not for valid searches without a result.
This change covers both cases.
Ignore case on MIME type check
Ignore case on file name check.
Support custom http headers on content type creation

* origin/pr/698:
  Support custom http headers on content type creation
  Some more cleanup
  Slight cleanup
  First step to content type headers
  tmp again
  tmp again
  tmp
  tmp
Fixed path to processors in some elements.
Updated resource sort processor

Allow to influence the parent node. This can be useful for sorting options in compontents that uses a sub-grid view of child resources instead using the tree (like Articles). Without this option it's necessary to include all parents untill the context-node (web/0) is reached.
Fixed condition validating package name during local upload

* origin/pr/11275:
  Ignore case on file name check.
  Bugfix in package name validation code