Allow Passing string to getAttributeValueObject
Allow Passing string to getAttributeValueObject

Allow passing string to `Collection::getAttributeValueObject()`

This is intended to line up interface more closly with User and File
objects


Former-commit-id: 717cf53988b21fa4826fcf604507eff63cdcf019
olsgreen/concrete5,concrete5/concrete5,haeflimi/concrete5,acliss19xx/concrete5,mlocati/concrete5,jaromirdalecky/concrete5,hissy/concrete5,biplobice/concrete5,olsgreen/concrete5,biplobice/concrete5,acliss19xx/concrete5,hissy/concrete5,rikzuiderlicht/concrete5,mlocati/concrete5,concrete5/concrete5,biplobice/concrete5,MrKarlDilkington/concrete5,hissy/concrete5,a3020/concrete5,mainio/concrete5,hissy/concrete5,mainio/concrete5,haeflimi/concrete5,haeflimi/concrete5,KorvinSzanto/concrete5,jaromirdalecky/concrete5,triplei/concrete5-8,deek87/concrete5,rikzuiderlicht/concrete5,rikzuiderlicht/concrete5,olsgreen/concrete5,concrete5/concrete5,acliss19xx/concrete5,deek87/concrete5,triplei/concrete5-8,mlocati/concrete5,KorvinSzanto/concrete5,KorvinSzanto/concrete5,deek87/concrete5,biplobice/concrete5,MrKarlDilkington/concrete5,haeflimi/concrete5,jaromirdalecky/concrete5,concrete5/concrete5,jaromirdalecky/concrete5,MrKarlDilkington/concrete5,a3020/concrete5,deek87/concrete5,triplei/concrete5-8,mainio/concrete5,mlocati/concrete5