#Shoopdawoop
from . import CuraEngineBackend

from UM.Preferences import Preferences

def getMetaData():
    return { "name": "CuraEngine Backend", "type": "Backend" }

def register(app):
    Preferences.addPreference("BackendLocation","../PinkUnicornEngine/CuraEngine")
    return CuraEngineBackend.CuraEngineBackend()


#Shoopdawoop
from . import CuraEngineBackend

from UM.Preferences import Preferences

def getMetaData():
    return { "name": "CuraEngine Backend", "type": "Backend" }

def register(app):
    Preferences.addPreference("BackendLocation","../PinkUnicornEngine/CuraEngine")
    engine = CuraEngineBackend.CuraEngineBackend()
    app.setBackend(engine)
    #engine.addCommand(TransferMeshCommand())

--- 
+++ 
@@ -8,6 +8,5 @@
 
 def register(app):
     Preferences.addPreference("BackendLocation","../PinkUnicornEngine/CuraEngine")
-    engine = CuraEngineBackend.CuraEngineBackend()
-    app.setBackend(engine)
-    #engine.addCommand(TransferMeshCommand())
+    return CuraEngineBackend.CuraEngineBackend()
+
Update plugin's register functions to return the object instance instead of performing the registration themselves
