CRM-15140 Recognise that ksort() returns a boolean rather than an array; prevent notice by replacing empty() with isset(); and prevent side-effect by not sorting
Revert isset() back to \!empty()
Merge pull request #187 from kenwest/CRM-15140

CRM-15140 fix metatag module support
Merge remote-tracking branch 'upstream/7.x-4.5' into 7.x-4.5-7.x-master-2014-11-14-11-21-36