While not a big deal for users, this is a full code refactoring to simplify maintainability and upcoming changes. Now can recommend project as nice example of modern embedded software development :).

From user's point of view - disabled integral part of PID by default. Everything else makes sense for developpers only.

If you wish dive into details, see changelog: https://github.com/speedcontrols/ac_sc_grinder/blob/master/CHANGELOG.md.