Release 2.1.0

Fetched from heiseonline/shariff:

• Improved build process (heiseonline#326).
• Fixed creator being appended to title even though data-title has been set (heiseonline#328).
• Replaced third party Java backend in readme (heiseonline#332).
• Name is diaspora* and not Diaspora (heiseonline#342).
• Fixed canonical URL handling (heiseonline#345).
• Removed googleplus service (heiseonline#348).
• Added Pocket service (heiseonline#349).
• Fixed typo in README (heiseonline#350).
• Upgraded dependencies.

This version 2.1.0 of Shariff-Plus is equal to Shariff 3.1.1 plus the facebooklike service.

Note that the Google+ service has been removed due to the shutdown of Google+.
See https://developers.google.com/+/integrations-shutdown
and https://developers.google.com/+/web/+1button/:

Google+ APIs will be shut down on March 7, 2019. This includes Google+ Sign-in. Learn more.
Google+ integrations for web and mobile apps will also cease to function March 7, 2019. Learn more.
This will be a progressive shutdown, with intermittent failures starting as early as January 28, 2019.