Display launcher options in command-line help
Added --verbose command-line option
Added --update command-line option

- the `--update` option can be used to update Chunky via the command-line

fixes #224 (github)
Added --version command-line option
Added -version command-line option
Added --setup command-line option

- the `--setup` option allows configuring the Java memory limit and JVM options
  in headless mode

fixes #211 (github)
Added -snapshot command