* Replace all occurences of Piwik in english translations of Actions plugin
* translation update
* Replace all occurences of Piwik in english translations of API plugin
* translation update
* Replace all occurences of Piwik in english translations of core
* replace Piwik occurrences
* Rename widget piwik.org blog => matomo.org blog
* fix widget name
* replaced some more piwik mentions
* Renamed to Matomo a few strings
* Replaced more strings to Matomo in JSON files, twig templates
* Replaced more strings to Matomo in INI file
* Replaced more strings to Matomo in API docs, error messages, feedback forms
* introduce API.getMatomoVersion and ExampleAPI.getMatomoVersion API + deprecate old ones