Major upgrades (could use more testing)

- Python 3 (only)
- Django 1.9
- Upgrade frontend deps
- Improve static file handling

mailadmin/models.py

@@ -4,13 +4,13 @@ from django.db import models
 
 
 class OrgUnit(models.Model):
-    def __unicode__(self):
+    def __str__(self):
         return self.name
 
     name = models.CharField(max_length=500)
     is_active = models.BooleanField(default=True)
-    admin_groups = models.ManyToManyField(Group, null=True, blank=True, related_name='admin_orgunits')
-    member_groups = models.ManyToManyField(Group, null=True, blank=True, related_name='member_orgunits')
+    admin_groups = models.ManyToManyField(Group, blank=True, related_name='admin_orgunits')
+    member_groups = models.ManyToManyField(Group, blank=True, related_name='member_orgunits')
     created = models.DateTimeField(auto_now_add=True)
     update = models.DateTimeField(auto_now=True)
     inside_id = models.IntegerField(null=True, blank=True)
@@ -27,7 +27,7 @@ class PrefixQueryset(models.QuerySet):
 
 
 class Prefix(models.Model):
-    def __unicode__(self):
+    def __str__(self):
         return self.name or ''
 
     name = models.CharField(max_length=500, blank=True, null=True)