[#34026] Improved search functionality in list views

Tracker item: http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=34026&start=0

This PR fixes 2 issues in pretty much all search views in the admin side:
* leading/trailing spaces are not ignored
* ```foo bar``` will not match ```foo xxx bar```

So to test:
* Search for the beginning part of something in the list and add a space before it.
* Search for the ending part of something in the list and add a space after it.
* Search - for example - for something that has three parts/words. But only enter the first and last part/word in the search field (separated by a space).

Unpatched the above should not return the item you are looking for. With this fix it should.

Check the Files changes to see which views are affected (and should be tested).