Additional Left/Right Modifiers + Win

[nolan778]

Summary of changes

Only affects Win32KeyBoard, as I'm unfamiliar with how to make similar changes in the other keyboards.

• Add Left and Right Variants of Ctrl, Shift, and Alt Modifiers (Existing modifier values unchanged)
• Add additional Windows key modifier (Left, right and combined)
• Add convenient function to return the whole modifier bit field

With left and/or right modifiers active, the combined modifier is also active. Both left/right must be inactive for the combined modifier to deactivate. This should only affect client code if they are comparing the entire bit field. However, the function to return the full bit field did not exist before this pull request.

[Ybalrid]

I'm gonna take a look at this. Somehow GitHub is not sending to me all the notifications from this repository and I did not see this PR

[Ybalrid]

This looks fine to me. I will test these, and either merge this right away, or try to add these modifiers at least on the Linux/X side myself

[Ybalrid]

I'm happy with this!