added a flag for controlling whether emitted XML is formatted or not and made a couple whitespace tweaks to the test descriptors so canonicalization works right.
added emitting a newline after <br /> tags
expanded unparse to better handle line breaks and symbol groups w/in reminder text
reimplemented unparse in a much more intelligible way
fixed a couple null issues when writing XML descriptors
pulled the 'help' command name into a constant, and explicitly used it when registering the command with JCommander
removed commandNames from the @Parameters annotation since the names are explicitly registered w/in CardCreator
added an 'md2xml' command that will convert a Markdown descriptor to the equivalent XML descriptor