Exclude formats with ! when opening

[radarhere]

Currently, to prevent opening a file in a certain format, without limiting your access to any other format, you can

from PIL import Image
Image.init()
Image.open(path, formats=[f for f in Image.ID if f != "EPS"])

or

from PIL import Image, EpsImagePlugin
Image.ID.remove("EPS")
Image.open(path)

It would be nice if there was a simpler way. This PR suggests

from PIL import Image
Image.open(path, formats=["!EPS"])

And yes, I suggest that Image.open(path, formats=["EPS", "!EPS"]) still does not allow an EPS image to be opened.

[hugovk]

Right, so:

Image.open(path)  # tries all, default formats=None
Image.open(path, formats=None)  # tries all
Image.open(path, formats=["JPEG"])  # only tries JPEG
Image.open(path, formats=["!EPS"])  # tries all but EPS
Image.open(path, formats=["EPS", "!EPS"])  # tries all but EPS
Image.open(path, formats=["JPEG", "!EPS"])  # only tries JPEG, !EPS has no effect

That last one could be surprising, but it's probably okay.

[radarhere]

Image.open(path, formats=["EPS", "!EPS"]) # tries all but EPS

I originally thought this should try none, but it's an edge case that could be debated. I've pushed your suggestions, and gone with trying all except EPS.