Remove unneeded __futures__ imports

No longer needed with Python 2 support dropped.

bin/player-account-step1.patch

@@ -4,7 +4,6 @@ index ec5fc29..62b7936 100644
 +++ b/evennia/comms/migrations/0015_auto_20170706_2041.py
 @@ -2,7 +2,12 @@
  # Generated by Django 1.11.2 on 2017-07-06 20:41
- from __future__ import unicode_literals
  
 -from django.db import migrations
 +from django.db import migrations, connection
@@ -60,7 +59,6 @@ index b27c75c..6e40252 100644
 +++ b/evennia/objects/migrations/0007_objectdb_db_account.py
 @@ -2,21 +2,31 @@
  # Generated by Django 1.11.2 on 2017-07-05 17:27
- from __future__ import unicode_literals
  
 -from django.db import migrations, models
 +from django.db import migrations, models, connection
@@ -104,7 +102,6 @@ index 80161a1..10fb225 100644
 +++ b/evennia/objects/migrations/0009_remove_objectdb_db_player.py
 @@ -2,7 +2,12 @@
  # Generated by Django 1.11.2 on 2017-07-06 20:41
- from __future__ import unicode_literals
  
 -from django.db import migrations
 +from django.db import migrations, connection
@@ -144,7 +141,6 @@ index 99baf70..23f6df9 100644
 +++ b/evennia/scripts/migrations/0009_scriptdb_db_account.py
 @@ -2,21 +2,31 @@
  # Generated by Django 1.11.2 on 2017-07-05 17:27
- from __future__ import unicode_literals
  
 -from django.db import migrations, models
 +from django.db import migrations, models, connection
@@ -188,7 +184,6 @@ index d3746a5..20fa63f 100644
 +++ b/evennia/scripts/migrations/0011_remove_scriptdb_db_player.py
 @@ -2,7 +2,12 @@
  # Generated by Django 1.11.2 on 2017-07-06 20:41
- from __future__ import unicode_literals
  
 -from django.db import migrations
 +from django.db import migrations, connection

evennia/accounts/migrations/0008_auto_20190128_1820.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 18:20
-from __future__ import unicode_literals
 
 import django.contrib.auth.validators
 from django.db import migrations, models

evennia/comms/migrations/0017_auto_20190128_1820.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 18:20
-from __future__ import unicode_literals
 
 from django.conf import settings
 from django.db import migrations, models

evennia/help/migrations/0003_auto_20190128_1820.py

@@ -1,7 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 18:20
-from __future__ import unicode_literals
-
 from django.db import migrations, models
 
 

evennia/objects/migrations/0010_auto_20190128_1820.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 18:20
-from __future__ import unicode_literals
 
 from django.conf import settings
 import django.core.validators

evennia/scripts/migrations/0012_auto_20190128_1820.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 18:20
-from __future__ import unicode_literals
 
 from django.conf import settings
 from django.db import migrations, models

evennia/server/migrations/0002_auto_20190128_2311.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 23:11
-from __future__ import unicode_literals
 
 from base64 import b64encode
 from django.db import migrations

evennia/typeclasses/migrations/0011_auto_20190128_1820.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-28 18:20
-from __future__ import unicode_literals
 
 from django.db import migrations, models
 import evennia.utils.picklefield

evennia/typeclasses/migrations/0012_attrs_to_picklev4_may_be_slow.py

@@ -1,6 +1,5 @@
 # -*- coding: utf-8 -*-
 # Generated by Django 1.11.16 on 2019-01-30 20:56
-from __future__ import unicode_literals
 
 from copy import deepcopy
 from base64 import b64encode, b64decode