Image loading failure on linux

[haraldsteinlechner]

https://github.com/aardvark-community/DevILSharp/issues/3

Possible solutions:

• require users to install libdevil-dev
• provide a "better" devilsharp prebuilt
• switch to pfim

I think switching to pfim is long-term the best solution. For TIFFs however devil will still be required. Let us first wait for the DevILSharp issue for now.

thanks Andreas for debugging!

[haraldsteinlechner]

actually i just figured out that it was already noted in the readme but totally forgot about it. I will merge develop to main to make this more apparent on the main branch