Updated Changelog for the upcoming 13.0.0 release

Set new version 12.11.0 for next release

Merge pull request #746 from claudep/changelog12.10

Completed the CHANGES file for version 12.10.0

Merge pull request #746 from claudep/changelog12.10

Completed the CHANGES file for version 12.10.0

sorl/thumbnail/engines/pil_engine.py - Changed code to a more readabl…

…e format.

Updated CHANGES for 12.8.0

Bump version (#656)

Correction in convert_engine with unknown exif orientation

Version 12.6.2 (#615)

Re-add Python 3.4 and 3.5 definitions + change log for #610