Pipe ('|') as OR in search filter in Extension Manager::Manage (Issue 4494)

Adding option to use pipe ('|') as OR in search filter in Extension Manager: Manage

## Original Report

![screen shot 2014-10-09 at 16 02 16](http://issues.joomla.org/uploads/1/426b6682482c4ca9e6207cf27df1e8b7.png)
#### Steps to reproduce the issue
- in admin, go to the menu "Extensions > Extensions Manager"
- select "Manage" submenu
- type "module|category|contact" in the search box and click on search
since Joomla 3.3.6, no results will be found

you can check with the direct url :
/administrator/index.php?option=com_installer&view=manage&filter_search=module|category|contact
and get no results too !

#### Expected result
in Joomla 3.3.3 and before, the filter_search will parse the "|" char and displays results by the "or" operator (see the attached PNG screen below)


#### Actual result



#### System information (as much as possible)
- Joomla 3.3.3 : the 'OR' operator works
- Joomla 3.3.6 : the 'OR' operator doesn't work

#### Additional comments

@madasha Please add a @since tag to the new function.