Whitespace only.
Minor changes in log messages.

refs #129
Improve constructor documentation.

refs #129
Fix bug introduced when inheriting from "dict" instead of "object".

Back then the __getitem__() and __setitem__() methods were disabled sind a "dict" already has them, but instead of using the dict structure to store key-value pairs itself, an additional dict was created inside of it. Therefore, accessing the outer dict would not do anything.

refs #129