v0.4.0

• Refactor: rename createComponent to defineComponent (the createComponent function is still there but deprecated) #230
• Fix: correct the symbol check; fixes the compatibility issue in iOS 9 #218
• Fix: avoid accessing undeclared instance fields on type-level; fixes Vetur template type checking; fixes vue-router type compatibility #189
• Fix: onUnmounted should not be run on deactivated #217