(#485) make drawable and drawableName optional for scene2d image factory

[Quillraven]

PR for #485.

I did not adjust the factory methods for Texture, TextureRegion and NinePatch because I think they will throw an exception, but more importantly, I think in those cases it does not make sense. Drawable and drawable name do make sense because in a Skin, from what I know, you can reference Drawables and in the case of an image they are optional.

[czyzby]

Thanks for the PR, I left some minor comments.

[Quillraven]

Issues should be resolved now. Regarding .editorconfig: I had a quick look and I could only find that there are IntelliJ specific properties that are supported. I guess the "star_import" properties are the ones that would be needed. But since they have the prefix "ij_" it will most likely only work in IntelliJ.

The thing that I did to solve it was a setting directly in IntelliJ:

The default setting was "Use import with '*' when at least 5 names used / 3 names used

[czyzby]

Thanks, the changes should be available in the snapshot release shortly. I'll try to update the changelog and possibly push a new release over the weekend.

[czyzby]

Just wanted to say that automatic snapshot upload failed, since I had to regenerate an access token into Maven central repository. Should be fixed now.

[Quillraven]

Haha had the same issue with Fleks the last time. Welcome to the club 😉