Merge branch 'feature_yggdrasil' into develop

Conflicts:
	gui/MainWindow.cpp
	logic/OneSixInstance.h

Fix missing session id functionality for legacy and old onesix.

logic/LegacyInstance.h

@@ -80,7 +80,7 @@ public:
 	virtual void setShouldUpdate(bool val);
 	virtual Task *doUpdate();
 
-	virtual MinecraftProcess *prepareForLaunch(LoginResponse response);
+	virtual MinecraftProcess *prepareForLaunch(MojangAccountPtr account);
 	virtual void cleanupAfterRun();
 	virtual QDialog *createModEditDialog(QWidget *parent);
 
@@ -93,4 +93,4 @@ public:
 protected
 slots:
 	virtual void jarModsChanged();
-};
+};