alphabetized requirements and upgraded to roughly late 2018, in line with...

alphabetized requirements and upgraded to roughly late 2018, in line with django 2.1, which we're using as a stepping stone to the even later 2.2 lts goal

requirements.txt

-DateTime==4.0.1
-Django>1.11, <1.12
-Pillow==2.9.0
-Whoosh==2.6.0
-argparse==1.2.1
-boto==2.38.0
-django-autoslug==1.9.3
-django-braces==1.9.0
+boto==2.49.0
+DateTime==4.3
+Django>2.1, <2.2
+django-autoslug==1.9.6
+django-braces==1.14.0
 django-cas-client==1.5.3
-django-crispy-forms==1.6.1
-django-gravatar2==1.4.0
-django-haystack==2.7.0
-django-model-utils==2.6
+django-crispy-forms==1.8.1
+django-gravatar2==1.4.4
+django-haystack==2.8.1
+django-model-utils==3.2.0
 django-piwik==0.1
 django-randomslugfield==0.3.0
-django-ratelimit==0.6.0
-django-redis-cache==1.6.4
+django-ratelimit==2.0.0
+django-redis-cache==1.8.1
 django-smtp-ssl==1.0
-django-storages==1.1.8
-djangorestframework==3.5.3
-docutils==0.12
-flake8==3.0.4
-gunicorn==19.6.0
-mccabe==0.5.2
+django-storages==1.7
+djangorestframework==3.9.4
+docutils==0.15.2
+flake8==3.6.0
+gunicorn==19.10.0
+mccabe==0.6.1
 mysqlclient==1.3.14
-pep8==1.6.2
+pep8==1.7.1
+Pillow==5.3.0
+pycodestyle==2.4.0
 pyflakes==1.0.0
 pyisbn==1.0.1
 python-dateutil==2.4.1
 pytz==2014.10
-requests==2.11.1
 redis==2.10.5
+requests==2.11.1
 selenium==2.45.0
 six==1.10.0
-wsgiref==0.1.2
+Whoosh==2.6.0
 zope.interface==4.1.2