Fix truncate filter as String.prototype.head is no more.
Fix truncate filter as String.prototype.head is no more.

ashwinrayaprolu1984/ringojs,Transcordia/ringojs,Transcordia/ringojs,ringo/ringojs,Transcordia/ringojs,ashwinrayaprolu1984/ringojs,oberhamsi/ringojs,ashwinrayaprolu1984/ringojs,ringo/ringojs,oberhamsi/ringojs,ashwinrayaprolu1984/ringojs,ringo/ringojs,oberhamsi/ringojs,Transcordia/ringojs,ringo/ringojs