Add workflows per document type view

Make workflows, workflows states, workflow transitions column
sortable. Show completion and intial state in the workflow
proxy instance menu list.

Signed-off-by: Roberto Rosario <roberto.rosario.gonzalez@gmail.com>

mayan/apps/document_states/models.py

@@ -71,6 +71,7 @@ class Workflow(models.Model):
             return self.states.get(initial=True)
         except self.states.model.DoesNotExist:
             return None
+    get_initial_state.short_description = _('Initial state')
 
     def launch_for(self, document):
         try: