Lcm-spy: Add cli params for the window title

[judfs]

I use LCM with multiple multicast addresses at the same time. It'd be useful for my team if there were option to have more detailed window titles than just "LCM Spy" when using multiple windows.

  -t, --title [LABEL]    Display LABEL in the window title
  --title-url            Display the LCM URL in the title

Example usages:

./lcm-java/lcm-spy --title 'Alice' --title-url
./lcm-java/lcm-spy -l 'udpm://239.255.76.67:8888' --title-url
./lcm-java/lcm-spy -t Bob

Added public static LCM.getDefaultURL.

I made and used WindowTitleOptions as I would in C. I find this clean enough, but if desired I can add java style boilerplate and maybe follow a builder pattern or something.

After feedback, I'd like to add these options [and maybe also --title-filename] to lcm-logplayer-gui.

[kyonifer]

Looks good, thanks.