Migrated project to .NET Standard 2.0

[SuNNjek]

Hi,

since this project is still using .NET 4.0 I've taken the liberty to migrate it to .NET Standard 2.0, making it run cross-platform.

I've also made some changes to the test project to make it run in the latest Visual Studio and modified the .gitignore to make it ignore all the VS related files.

[castarco]

Hi @SuNNjek , I'm wondering if you are interesting on taking the ownership of the project. I'm not maintaining it, I don't have much time, and actually I'm not using the library anymore (it was used in a proprietary project some time ago, but I moved to another job).

Relative to the PR, I guess you checked that the library can be properly compiled and linked, right?

P.D.: I even lost the signing key that I used to release versions of it...

[SuNNjek]

I don't know if I'm the right person to take over this project because I admittedly don't understand the maths involved 😰 Otherwise I'd be happy to

And yes, I checked that the library compiles (and since CI works again, Travis agrees with me there :P). Creating a NuGet package also still works.

[DillyGoatGruff]

Hi @SuNNjek, I actually work a lot in color spaces and understand the math. However I am very new to Github so I would not feel comfortable taking ownership (yet at least). I know your changes are from a few years ago but if you were still interested in this project I would be willing to work on it with you and if you are not wanting the responsibility, I could take ownership after a period of time.