Allow launching instances via command line arguments

[finalsliver]

Suggestion by Sammko on the forum

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This is an AMAZING app Thanks alot Forkk.

Also have you thought about Command Line Argument parsing? like if i do:

"MultiMC.exe -Instance n"

it would launch Instance with index n (zero based) cause that would be pretty amazing! and it is not even hard to do in .NET

seems like it might be a good idea.

[Forkk]

Good idea, I'll see what I can do.