[DS-1085] Apply patch (slightly updated) from Jira ticket
Resurrected build.xml's help menu item 'clean_backups'
Merge pull request #187 from MinDogger/DS-1123

Resurrected build.xml's help menu item 'clean_backups'
add 'test_database' target to ant command help
Merge pull request #165 from helix84/DS-1085

[DS-1085] EPerson last_active field is defined but never filled

Tested, appears to work.  No negative reviews after several weeks.
Merge remote-tracking branch 'upstream/master'