when commands like `appdebug verbose` are used rather than `appdebug 2`, the command would fail because Verbose != verbose. The enum conversion is now case-insensitive.
Some overloads that had the first argument as an Exception were calling the _logger.Write method with a null where the message template should have been, causing messages logged with that overload to be swallowed and not logged.
In an effort to make it easier to use the logging mechanism, I added 4 overloaded methods for each level to allow for logging exceptions at any level, not just error.
I also added overloads for each level to the extensions so that an exception can be logged at any level, not just error.
