Give link_to_model key'ing ability
Give link_to_model key'ing ability

``link_to_model`` can now be given as a callback where only a ``key`` keyword argument is provided.  This allows the helper to target related fields by taking the primary instance and converting it to some other model instance, likely a ForeignKey field.

CloudNcodeInc/django-datatable-view,johnrtipton/django-datatable-view,greenbender/django-datatable-view,pivotal-energy-solutions/django-datatable-view,annabed/django-datatable-view,johnrtipton/django-datatable-view,jangeador/django-datatable-view,greenbender/django-datatable-view,pivotal-energy-solutions/django-datatable-view,addgene/django-datatable-view,CloudNcodeInc/django-datatable-view,greenbender/django-datatable-view,annaproch/django-datatable-view,RamezIssac/django-datatable-view,doganmeh/django-datatable-view,annaproch/django-datatable-view,jangeador/django-datatable-view,annabed/django-datatable-view,RamezIssac/django-datatable-view,annaproch/django-datatable-view,annabed/django-datatable-view,RamezIssac/django-datatable-view,pivotal-energy-solutions/django-datatable-view,addgene/django-datatable-view,doganmeh/django-datatable-view,johnrtipton/django-datatable-view,doganmeh/django-datatable-view,CloudNcodeInc/django-datatable-view,jangeador/django-datatable-view,addgene/django-datatable-view