Include in the survey results the anonymous responses

The query included a 'Users.uID = btSurveyResults.uID' in the WHERE clause
This leads to skipping anonymous results (for which we have an empty
btSurveyResults.uID)

Using a LEFT JOIN allows including also the anonymous results
Merge branch 'fix-surveys-report' of https://github.com/mlocati/concrete5 into mlocati-fix-surveys-report
Merge branch 'master' of github.com:concrete5/concrete5
fixing page type toolbar bug