Clean pip requirements

requirements.txt

@@ -16,16 +16,12 @@ dj-database-url==0.5.0
 Django==1.11.16
 django-cors-headers==2.1.0
 django-filter==2.0.0
-django-heroku==0.2.0
 django-lazysignup==2.0.0
 django-model-utils==3.0.0
-django-rest-swagger==2.1.2
 django-simple-history==2.4.0
-djangoql==0.8.9
 djangorestframework==3.7.7
 djangorestframework-camel-case==1.0b1
 djangorestframework-jsonapi==2.2.0
-drf-openapi==0.9.9
 drf-yasg==1.10.2
 flex==6.13.1
 future==0.16.0
@@ -44,15 +40,13 @@ kombu==4.2.1
 MarkupSafe==1.0
 mock==2.0.0
 model-mommy==1.5.1
-mysqlclient==1.3.10
 nose==1.3.7
 openapi-codec==1.3.2
 parameterized==0.6.1
 parso==0.1.1
 pbr==4.0.2
 pexpect==4.5.0
 pickleshare==0.7.4
-ply==3.10
 prompt-toolkit==1.0.15
 psycopg2==2.7.4
 psycopg2-binary==2.7.4