Fix for show username in member permissions page

The issue Cadasta#626 suggest that if full name is empty
then username should be set in member permission page. This pull request contains fix for it as well as
member list page, when full name is empty member column gets blank. So I include to display username if full name is not
present

cadasta/accounts/models.py

@@ -67,6 +67,17 @@ def get_full_name(self):
         """
         return self.full_name
 
+    def get_display_name(self):
+        """
+        Returns the display name.
+        If full name is present then return full name as display name
+        else return username.
+        """
+        if self.full_name != '':
+            return self.full_name
+        else:
+            return self.username
+
 
 @receiver(models.signals.post_save, sender=User)
 def assign_default_policy(sender, instance, **kwargs):

cadasta/templates/organization/organization_members.html

@@ -34,7 +34,7 @@ <h2>{% trans "Members" %}</h2>
             <tbody>
             {% for user in organization.users.all %}
               <tr class="linked" onclick="window.document.location='{% url 'organization:members_edit' slug=organization.slug username=user.username %}';">
-                <td>{{ user.get_full_name }}
+                <td>{{ user.get_display_name }}
                   <div class="hidden-sm hidden-md hidden-lg">
                     {{ user.username }}<br />
                     {{ user.email }}

cadasta/templates/organization/organization_members_edit.html

@@ -13,7 +13,7 @@
   <div class="row">
     <!-- Main text  -->
     <div class="col-md-12 main-text">
-      <h2>{% trans "Member" %}: <span class="text-capitalize">{{ object.get_full_name }}</span></h2>
+      <h2>{% trans "Member" %}: <span class="text-capitalize">{{ object.get_display_name }}</span></h2>
       <form method="POST" action="" class="org-member-edit" novalidate>
       {% csrf_token %}
         <div class="row">