Make it possible to more fully make the namespace class so that I can implement
unit tests.
Fix a couple of errors found in unit testing.
I'm about half done with the append handler.
Fix a couple of errors found in unit testing.  First, the flags should be zero unless otherwise specified.  Second, it wasn't handling
parsing date or flag data after specifying a mailbox in a literal string.
Do some refactoring because it's become apparent that trying to put tests for
all the command handlers into a single file is just dumb.
Fix it until it compiles.