Better gesture class implementation - fixes #8220

[paulvanharen]

A revised implementation of the gesture comparison code, fixing #8220. Also, the API is extended, backwards compatible, documentation is updated and unit tests have been added.

Maintainer merge checklist

• [ ] Title is descriptive/clear for inclusion in release notes.
• [ ] Applied a Component: xxx label.
• [ ] Applied the api-deprecation or api-break label.
• [ ] Applied the release-highlight label to be highlighted in release notes.
• [ ] Added to the milestone version it was merged into.
• [ ] Unittests are included in PR.
• [ ] Properly documented, including versionadded, versionchanged as needed.

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[paulvanharen]

@misl6: All your feedback has been processed. Is there anything you want me to do to complete this pull request?