Headless operation

[mbilotta]

Sooner or later Swing will be deprecated in favor of JavaFX (or somewhat else) but I don't plan to rewrite the UI in the near future. That stated, a simple way to make Julia future-proof is to improve its CLI to provide users a complete headless experience.

[mbilotta]

Next steps:

• Set rect using center and diameter
• Save partial renderings
• Bulk image rendering (--bulk parameter of the generate command)
• describe command that should take a JIM and output the command line that generates it
• replace --ignore-intermediate-image with --no-iimg-input and also add --no-iimg-output
• save producer output (logs) to file
• pass options to ImageIO (e.g.: compression level, progressiveness etc.)