Add modified reinhard support

[andreped]

This PR extends Reinhard and adds a new method argument, which enables the user to choose between traditional Reinhard and the Modified version. All backends supported.

This PR can be merged after #27 , as this branch was based on that branch.

[carloalbertobarbano]

Hi, I am finally back from vacation. I am merging all the pending PR, however I see some tests are failing due to FAILED tests/test_tf.py::test_macenko_tf - AttributeError: module 'numpy' has no attribute 'float' ..we are using np.float in conversions, which was removed starting from numpy 1.24.0. Should we provide a fix?

[carloalbertobarbano]

For Modified Reinhard, nice work. I was thinking maybe of refactoring it using a sublcass ModifiedReinhardNormalizer rather than the method argument, in order to keep consistency; but it's not strictly mandatory for now. What do you think?

[andreped]

Should we provide a fix?

Definitely. I just did not observe that on my local testing setup, as I was using an older numpy version. Using np.float32 should also be backward compatible. Seems like you are making the necessary changes now in your own development branch?

For Modified Reinhard, nice work. I was thinking maybe of refactoring it using a sublcass ModifiedReinhardNormalizer rather than the method argument, in order to keep consistency; but it's not strictly mandatory for now. What do you think?

That was actually my first suggestion, but then I realized how extremely similar the two variants were, and I thought having a method flag makes more sense. But up to you :]

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EDIT:
Also note that method arg might become relevant for other methods as well in the future, as methods like Macenko have modified variants themselves.

[carloalbertobarbano]

Okay, let's keep the method argument for now. Yes, I will merge everything onto the development branch and then I will fix the numpy tests