Use Dev Launch Injector to ensure that the launch options are always kept upto date. (#138)

* Generate pre-launch classes to set the run args and system property's
Will remove the need to regen the run configs each time the game is updated

* fix minor thing.

* Small cleanup

* Another small rename + remove testing code

* Remove import

* Add basic auto upgrade path, put the launch classes in a package

* Suggested cleanups

* Use dev-launch-wrapper

* Remove old classes

* Rename to dev-launch-injector

* Update more things I forgot about

src/main/java/net/fabricmc/loom/LoomGradleExtension.java

@@ -179,6 +179,10 @@ public class LoomGradleExtension {
 		return natives;
 	}
 
+	public File getDevLauncherConfig() {
+		return new File(getRootProjectPersistentCache(), "launch.cfg");
+	}
+
 	@Nullable
 	private static Dependency findDependency(Project p, Collection<Configuration> configs, BiPredicate<String, String> groupNameFilter) {
 		for (Configuration config : configs) {