Skip border functionality

[SerodioJ]

• adapt GLCM class to compute GLCM with information only from the selected window, without neighboring information that is only present on the window pair, by skipping the border.

The image below exemplifies the process for each direction

Note that the default behavior is the same as it was previously (skip_border = False).

[SerodioJ]

• update tests

[SerodioJ]

Hi @Eve-ning,
I modified the GLCM class a bit so that the results would match when computing the same features with scikit-image (skimage.feature.graycomatrix followed by skimage.feature.graycoprops )

I also intend to add some features, but I will leave it to a different PR

• Entropy: $\sum_{i,j=0}^{N-1} {P_{i,j}(-lnP_{i,j}})$
• Energy: $\sqrt{ASM}$
• Standard Deviation: $\sqrt{Variance}$

The last two are just the square root of already implemented features.

[Eve-ning]

Hi @SerodioJ, thanks for your contribution, I'll likely only be able to get to reviewing this next month!

[SerodioJ]

Hi @Eve-ning. Will you be able to review this PR this month?

[Eve-ning]

Hi @Eve-ning. Will you be able to review this PR this month?

I'll try to, I can't promise this as I've many other obligations. Your team can opt to pip install from your GitHub branch if necessary