User parameter changes

1. User cannot change number of messages per broadcast; the default of 1
is always used.

2. User can choose time unit for frequency: seconds, minutes, hours,
days, weeks.

3. User can choose UDP port (default is 45678).
Added time unit to command line

Added time unit parameter to command line. Also refactored
frequency/time unit logic from SimulatorDialog to SimulatorController.
Time override fields and silent/verbose

1. Added the ability to set time override fields, such that the value of
the specified fields in outgoing messages will be the current date/time
rather than whatever is in the XML file.

2. In a previous commit, the controller was changed so that verbose is
the default. This changes the console app to reflect that. Users used to
pass "-v" to turn on verbose output. Now they pass "-s" to turn off
verbose output.