Add TinyMCE4 specific commit to requirements.txt

requirements.txt

@@ -5,7 +5,7 @@ django-compressor>=2.1,<3
 django-sendfile<=0.4
 django-template-check>=0.3.0  # This should be in dev-requirements somehow
 bleach>=2.0.0,<2.1
-django-tinymce4-lite>=1.5,<1.6
+-e git+https://github.com/romanvm/django-tinymce4-lite.git@ac1715f5f1a92c775af3720b89dfb8417c2e11f0#egg=django-tinymce4-lite
 pytz
 rcssmin>=1.0.6
 djangorestframework>=3.6.2,<3.7