histedit: break _histedit function into smaller pieces (add _newaction) This is a part of bigger effort to refactor histedit. Initial steps are to break _histedit function into smaller pieces which will supposedly be more understandable. After this is done, I will have a better understanding of how histedit works and apply that to fix issue4800.

histedit: break _histedit function into smaller pieces (add _editplanaction) This is a part of bigger effort to refactor histedit. Initial steps are to break _histedit function into smaller pieces which will supposedly be more understandable. After this is done, I will have a better understanding of how histedit works and apply that to fix issue4800.

histedit: break _histedit function into smaller pieces (add _abortaction) This is a part of bigger effort to refactor histedit. Initial steps are to break _histedit function into smaller pieces which will supposedly be more understandable. After this is done, I will have a better understanding of how histedit works and apply that to fix issue4800.