Fix CollecionVersion::getAttribute Cache Issue
Fix CollecionVersion::getAttribute Cache Issue

Fix `CollectionVersion::getAttribute()` Cache Issue

`CollectionVersion::getAttribute()` caches attributes in an array based
on the attribute handle `akHandle`

When a Collection Attribute is requested with two different display
modes `$displayMode` in the same request the first one requested will
always be returned.

- Add `$akHash` value comprised of both attribute handle and display
  mode for hash key


Former-commit-id: 9b28dfb3649bdc011de8e705304dca89a0128afc
MrKarlDilkington/concrete5,mlocati/concrete5,hissy/concrete5,biplobice/concrete5,acliss19xx/concrete5,MrKarlDilkington/concrete5,haeflimi/concrete5,acliss19xx/concrete5,mainio/concrete5,biplobice/concrete5,rikzuiderlicht/concrete5,jaromirdalecky/concrete5,deek87/concrete5,jaromirdalecky/concrete5,olsgreen/concrete5,rikzuiderlicht/concrete5,hissy/concrete5,triplei/concrete5-8,a3020/concrete5,concrete5/concrete5,triplei/concrete5-8,hissy/concrete5,mainio/concrete5,deek87/concrete5,haeflimi/concrete5,KorvinSzanto/concrete5,jaromirdalecky/concrete5,rikzuiderlicht/concrete5,concrete5/concrete5,a3020/concrete5,biplobice/concrete5,hissy/concrete5,jaromirdalecky/concrete5,MrKarlDilkington/concrete5,deek87/concrete5,concrete5/concrete5,triplei/concrete5-8,mlocati/concrete5,concrete5/concrete5,olsgreen/concrete5,KorvinSzanto/concrete5,deek87/concrete5,acliss19xx/concrete5,mlocati/concrete5,mainio/concrete5,olsgreen/concrete5,KorvinSzanto/concrete5,haeflimi/concrete5,mlocati/concrete5,haeflimi/concrete5,biplobice/concrete5