Add interactive/visual pattern generation

[dnjohnstone]

@shogas created a script (https://github.com/shogas/sped_processing_playground/blob/master/pattern_gen_visualizer.py) for manually tweaking kinematical simulation parameters - it would be good to put this in to the diffsims code base

[pc494]

Did we drop the .as_signal() method?

[dnjohnstone]

I think we had to so that diffsims didn't depend on either pyxem or hyperspy. Not sure what we should do about that...

[pc494]

I think we had to so that diffsims didn't depend on either pyxem or hyperspy. Not sure what we should do about that...

That makes perfect sense, I'll write a numpy + matplotlib only implementation - I think it's worth having as functionality.

[pc494]

A similar functionality for parameter tweaking was added to pyxem but it relies on hyperspy for the plotting; see - pyxem/pyxem#451

The numpy + matplotlib solution was added by #25

[pc494]

Will combine this with my efforts on #7

[pc494]

The components of this that haven't been done should probably be in workflow. Until they are needed I'm not going to make a priority of this.