Faster implementation of nested tags (contact tags) for PRM.
Reduced db calls by 25%
Reduced calls by another 15%.
Merge branch 'master' into pd-699

Conflicts:
	mypartners/models.py
	templates/mypartners/includes/partner_card.html
Merge pull request #981 from DirectEmployers/pd-699

[PD-699] Contact tags in PRM overview