remove old image files

[nneveu]

Summary of changes

Removing image.py and fitting_tool.py. These files should have been deleted when the image and fit folders were refactored.

Additional notes

I'm still not happy with some of the file names/structure related to image/fit. That will have to wait for another PR.

This merge will close #225

[nneveu]

Of course I forgot to clean up the other files...working on it.

[pluflou]

@nneveu you need to make the PR from a branch on the main repo for the meme package to be installed otherwise the tests will fail when creating a PR to main (I'm starting to think that maybe this way of doing things isn't the most efficient way of doing things)

[nneveu]

I see, can we switch to Paul's suggestion then? And just import meme in the one place it's asked for?

[eloiseyang]

I think moving to Paul's suggestion in this case is fine. That being said, I think it's likely we will have to import a module from a private repo again. We can work out another solution when that happens.