REQUEST: Add start/calculate button

[vertigo220]

If the calculation is canceled, it's impossible to restart it. The only option is to close the window and right-click the file(s) and go through the whole process again. There should be a button to ideally resume the calculation (so if it's canceled partway through, it will remember the work done so far until the window is closed, allowing it to be resumed from that point) or, if that's not possible to re-initiate the calculation.

[o-l-a-v]

Would also be useful if changing settings for what algorithms to use, as after adding or removing algorithm(s) OpenHashTab does not recalculate.