Document how to set boolean flags when using marathon startup script

[lingmann]

Currently, there is no documentation on how to set boolean flags when using the Marathon startup script. Furthermore, it's difficult to even figure this out by looking at the source because the script is prepended to the jar. At a minimum, update --help so that it is at least self-documenting with regard to boolean flags. Even better, we should extract the startup script from the jar so that it is easier for users to see how marathon is configured and launched.

[ssk2]

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