Zend\Filter\StripNewlines: uppercase L to lowercase l

Fix for the [first comment on this page](http://framework.zend.com/manual/2.3/en/modules/zend.filter.set.html#comment-1034778432):

> "Zend\Filter\StripNewLines" doesn't work in Unix systems. The correct usage is "Zend\Filter\StripNewlines", with "l" instead "L".