Fix for #4727

Check if parameter is scalar before cast to string
If not throw InvalidArgumentException
Fix for #4727
Travis Fix

I always forget something about travis
Correction in the variable names
Tests Added and Message Changed
Fix for Int Filter

Found one more.
A Feel More

Check array in:
Zend\Filter\BaseName
Zend\Filter\Digits
Zend\Filter\HtmlEntities
Zend\Filter\RealPath
Travis Fix
Merge pull request #4734 from pauloelr/fix_filter_array_to_string

Fix for #4727
Merge branch 'hotfix/4734'

Close #4734
Fixes #4727