Support len() on Relation objects
Support len() on Relation objects

Sinar/mapit,opencorato/mapit,New-Bamboo/mapit,Code4SA/mapit,Code4SA/mapit,opencorato/mapit,New-Bamboo/mapit,chris48s/mapit,Code4SA/mapit,opencorato/mapit,chris48s/mapit,chris48s/mapit,Sinar/mapit