[LOGGER] Change inner workings (again)

[LOGGER] Change inner workings (again)

Change the inner workings of the RarslaveLogger class so that it has
four different message types: Fatal, Normal, Verbose, Debug. This also
adds the function printLoglevel() to the RarslaveLogger class. It will
print all messages at a certain loglevel.

Also update the unit tests so that they behave with the current workings of
the RarslaveLogger class.

Signed-off-by: Ira W. Snyder <devel@irasnyder.com>