Determine current ppg_status #3942

The current ppg_status logic was incorrect for back
entered data. This commit corrects this problem by
1) setting the ppg_status_date to the contact date
2) ordering ppg_status by ppg_status_date AND created_at

Alos included in this commit is bumping the version to 1.5.2
to reflect this hot fix for the deployed 1.5 version.