v1.2.0

This is the last release to support Python 2 and Django <2. It does not
contain any huge behavior changes, as to smooth migration to the next version. The
upcoming major release (v2) will drop Python 2 and Python 3.5 support.

• Changed to MIT License
• Fixes trying to write JPGs with opacity (#28)
• Better error messages (!25)

Tested with:

• Django 1.8, 1.9, 1.10, 1.11, 2.0, 2.1, 2.2, 3.0, 3.1 and 3.2.
• sorl-Thumbnail 12.4, 12.5, 12.6 and 12.7.
• Pillow 5, 6, 7 and 8.
• Python 2.7, 3.5, 3.6, 3.7, 3.8 and 3.9.