Updated the copyright year range.
Included Evgeny Kotelnikov in the list of contributors.
Included James Chapman in the list of contributors.
Fixed whitespace issues.
Preparation for the release of version 0.8.
Removed release-specific information.
Included Pepijn Kokke in the list of contributors.
Added .mailmap file.

The information from some Git commands, e.g. git shortlog -nse, is
better by using this file.