v0.7.0

• Improved performance and memory usage.
• Disabled expensive validation in production.
• Fixed rendering in React strict mode.
• Derivation.unsubscribeFromSources no longer clears list of sources.
• useModel, useDerived, and useReduced no longer dispose their value on "unmount".
• Removed notifyObservers parameter from ObservableValue.setValue.
• Support for @reduced decorator on getter properties.
• Events returned from getters in @events classes are memoized.
• Fixed disposing mutable models.