Add autosharpening for cards? Various resizing methods?

[Fixer-007]

I'm not an expert on this but I've noticed a lot of cards are kinda blurry and naturally autosharpen mode comes to mind (like option in image editors) as the way to mitigate this, along with option to select better resizing method (bilinear, bicubic, whatever), currently resizing just not good (uneven + blurry), at least in 2.10.1 that I've looked.

Crude example by sharpening in IrfanView: Before: After:

[joeraz]

Interesting idea. Usually, I've found that downsizing hi-res cardsets gets better results, but I know the resizing library has a few filters built in - I'll see if I can test them out.

[joeraz]

I added an option for resampling, but updating sharpness/brightness/contrast would be a bit more difficult.