Add Adventure Mode as an option when creating world (#757)

* per user config should be .gitignored

* add comment surrounding gitignore update

* make it wildcard

* add fullscreen to launch option struct

* remove redundant forward declaration and use fullscreen launch option in main

* add adventure mode option as well as adjust cycling logic

* Revert deleting *.user from end of .gitignore

* rework comments

.gitignore

@@ -435,4 +435,4 @@ build/*
 Minecraft.Client/Saves/
 
 # Visual Studio Per-User Config
-*.user
+*.user