Automatically crop whitespace before displaying texture

[Stacey Haffner]

Many textures have a lot of white space at the top and users would have a better experience if the program automatically detected where the whitespace stopped and the texture began. This would enable the texture display box to show a larger image of the actual texture.

[Stacey Haffner]

The preview will have a cropped version that centers around the actual usage. The user will be able to click on the image so that opens a window with the original image.

[orangemittens]

Since we're going to be eliminating this feature in the new fullscreen UI I think it's safe to mark this issue resolved.

[orangemittens]

Resolved.