Fix #357 Commandline option to reset Freeseer

Added 3 new options to freeseer-config

--reset                Removes the entire freeseer configuration
                       directory.
--reset-configuration  Removes freeseer.conf and plugins.conf from the
                       configuration directory.
--reset-database       Removes presentations.db from the configuration
                       directory. Resets the talk database.

Signed-off-by: Thanh Ha <thanh.ha@alumni.carleton.ca>