Fix flipped images in load, save, and snapshot

[sparshg]

Fixes #642 and the following

• window.save_image saves flipped image. This code snippet should save black (top) to white (bottom) gradient, but did the inverse.

  image = np.reshape(np.tile(np.arange(0, 256).astype(np.uint8), (256*3,1)).T, (256,256,3))
  print(image)
  window.save_image(image, "image.png")

• window.load_image would load flipped image of the input file.

Seems like this was due to #521 https://github.com/fury-gl/fury/pull/521/commits/ecd3408d523507da27e77f324d2c12247931fa36. I reverted this and save/load was fixed. Now window.record was broken due to #521 https://github.com/fury-gl/fury/pull/521/commits/0e448af7e84476cc7ad12b57484844a5423e1af4 which I had to revert.

At this point basically all the changes of #521 were reverted which flipped images on save/load/record. Now I had to fix #467 due to which #521 was opened. That means I had to simply flip the image array before saving in window.snapshot as we do in window.record. This will hence fail some tests that were written with window.snapshot producing flipped image arrays.

Edit: Too late to notice #720, it wasn't mentioned anywhere...

[skoudoro]

Hi @sparshg,

Thank you for doing this. I recommend you to generate the documentation and look if all images are ok. It seems you change makes other images to flip. Also, I recommend to run the test locally and check that everything is ok.

You can look at FURY website to check how to run the documentation and how to run the tests locally

[sparshg]

Fixed the tests, all passing now