config.get() doesn't return default values for certain keys

[lacymorrow]

I may be going crazy, but I've been experimenting with resetting the store to default values. For some reason my keyword

Running config.delete() and then restarting the electron starter app resets most settings to default, but not opacity, which returns a null value no matter how many times the store is recreated.

I worked around by manually resetting the default values.

This could be related to #58