Implemented AKContactInstantMessageViewCell cellWithDelegate:atRow:
Implemented AKContactHeaderViewCell cellWithDelegate:atRow:
Implemented AKContactDetailViewCell cellWithDelegate:atRow:
Implemented AKContactAddressViewCell cellWithDelegate:atRow:
Implemented AKContactSwitchViewCell cellWithDelegate:atRow:
Implemented AKContactDeleteButtonViewCell cellWithDelegate:atRow:
Implemented AKContactButtonsViewCell cellWithDelegate:atRow:
Implemented AKContactLinkedViewCell cellWithDelegate:atRow:
Moved cell constructors to their respective classes