* Update the contributors list.
* Update the version number.
* Sync zh and zh-hant versions.
* Move epub builder to the utils branch.
* Optimize all figure files using pngquant.
* Update copyright.
* Update Acknowledgements.
* Update buttons in README.
* Sync zh and zh-hant versions
* Update the list of contributors.
* Update time_complexity_simple_example.png
* Reduce size of the RGBA images for zh-hant version.
* Sync the zh-hant version of terminology.md
* Prepare 1.2.0 release
* Update the contributors list.
* Update bucket_sort.c
* Fix the comments in quick_sort.c
* Update the announce badge
* Sync zh and zh-hant versions
* Update contributors list.
* Sync zh and zh-hant versions.
* Sync zh and zh-hant versions.
* Update the contributors list
* Update the version number