Upgrade base requirements.

requirements/base.txt

@@ -1,16 +1,16 @@
-Django==1.10.4
-pytz==2015.7
+Django==1.11.2
+pytz==2017.2 # Updated from 2015.7
 django-widget-tweaks==1.4.1
-psycopg2==2.6.1
-django-libsass==0.6
-django_compressor==2.0
-python-dateutil==2.5.3
+psycopg2==2.7.1 # Updated from 2.6.1
+django-libsass==0.7 # Updated from 0.6
+django_compressor==2.1.1 # Updated from 2.0
+python-dateutil==2.6.0 # Updated from 2.5.3
 whoosh==2.7.4
-django-haystack==2.5.1
+django-haystack==2.6.1 # Updated from 2.5.1
 djangorestframework
 django-webpack-loader
 requests
 PyYAML
-djangorestframework-jwt==1.9.0
-django-multiselectfield==0.1.4
-mailchimp3==2.0.11
+djangorestframework-jwt==1.11.0 # Updated from 1.9.0
+django-multiselectfield==0.1.7 # Updated from 0.1.4
+mailchimp3==2.0.14 # Updated from 2.0.11