Include gender & age in Constituent Summary Report

This is a follow up of issue CRM-13279 which was resolved for the
Participant Listing report only. In the Constituent Summary Report the
gender and age are missing from selectable fields, order-by and filter.
The fix follows the same pattern as the one for issue CRM-13279
Merge pull request #4027 from magnolia61/(CRM-15223)-Include-gender-and-age-in-(constituent)-reports

Include gender & age in Constituent Summary Report