Improve logo example

[brettinman]

This is a less disruptive attempt at making the logos example a little more obvious for beginners.

This does three small things:

• Changes default png2asset arguments for GBC logo to use -noflip. The reasoning is that the GBC build for this example project defaults to GB and GBC compatibility (LCC flag -Wm-yc), so the default behavior for the image processing should match.
• Updates the readme with a little more context, and a note about noflip should the user need to remove the option for space efficiency reasons
• Adds the ability to set the rom title in the cartridge header