* To ensure that the "label filtering" works on all types of labels including special characters "' <> etc.  I refactored the SafeDecodeLabel filter function. 
 * Changed DataTableLabelFilter to use Piwik_API_ResponseBuilder directly rather than duplicating code
 * Added few tests cases 



git-svn-id: http://dev.piwik.org/svn/trunk@5774 59fd770c-687e-43c8-a1e3-f5a4ff64c105