Feature Request: Make the Manual CP Generation Process Interruptable

[rok5]

Sometimes auto fine tune doesn't find matching control point with good correlation. User would than possibly like to abort the process of adding control point. It is somewhat unintuitive and uneconomical that he must first click "add control point", only then can he press the "delete" button.

[Bruno Postle (brunopostle)]

re-setting category as this is a bug on all platforms

[Yuv (yuv)]

We need a finer grained possibility to abor the CP editing, possibly attached to the ESC and/or DEL key.

Users should be given the opportunity to abort the process at any time after:
* clicking the first point of the pair
* clicking the second point of the pair
* fine tuning the pair

Without having to go through the whole creation process.

[tmodes (tmodes)]

The generation process can now canceled with escape key.