Add option to close launcher after game is launched.

[Fefedu973]

Add option to : Close the launcher after launching the game. - Close the game if the launcher is closed. - Keep the launcher open after launching the game.

[dscalzi]

Close the launcher after launching the game.

Can be added

Close the game if the launcher is closed.

Already possible, disable "Launch game process detached from launcher" in the Minecraft settings of the launcher.

Keep the launcher open after launching the game.

Current default behavior.

[Ulysse2211]

Please add this, its almost been a year!

I've made it, gonna do a pull request now.