Improve implementation for Fix #84

[lviggiano]

See commit 3a08648, the if works just as fallback. If I call debugging aid methods like toString() or list() I don't see expansion working, since the default value is resolved at runtime not inside the internal structure in the properties file.

[aaronkavlie-wf]

Could really use this; toString() / list(System.out) do not align with your config interface, and if you include system properties and environment variables it leads to a lot of noise.