Implement basic commandline functionality.

- Use the already existing /LICENSE.txt for --license
- Store the --help text in /USAGE.txt
- Prepare for additional commandline arguments
Implement commandline option --set.

This is one of the first steps towards automation.
Added documentation for --set in help.txt.
Reformatted help.txt to wrap lines nicely,
in case the user's terminal doesn't already.
Avoid creating GUI on a non-Swing thread.

Force building EVERY part of the GUI on the EDT, even if that mean we need another anonymous class.
Let entity eat food that drops on their position, if entity is waiting.

This isn't exactly what we want Programs "encourage" to do,
but it feels "more natural" this way.
Add population diff to JStatusPane.
Implement commandline option --seed.
Implement commandline option --statistics.

See --help for detailed description how it works.
Internally using shutdown hooks, so NEARLY EVERY entry is written.
The only remaining problem might be the GUI terminating
WHILE main() is writing out data.
But that's not the intended use-case anyway;
see the upcoming --automate flag.
Implement commandline option --automate-for and companions.

See description in --help for usage, and what --no-gui,
--exit-after and --go-fast do.
Eye-candy: Maximize at start and one-touch expandable field.

- Make window maximized by default.
- Allow to one-touch-expand the JFieldPane to nearly the full window.
  Otherwise, the first this the user always does after startup
  is to hit the maximize-button.
Implement Pause and Go Fast.

Added Buttons in GUI to toggle these two settings.
Added commandline options to toggle these settings.
Added documentation for --help for these two settings.
Close scanner instance after usage and free resources.
Add keybinding for pause/unpause.
Implement and document reset button.

Also, make all parameters mutable, since we can reset the field.