Come up with a "mark" logo version for the app icon

[robinheinze]

On Android, the full "Ignite" name-based logo is very close to the edges due to the adaptive icon cropping, and doesn't really match the style of typical app icons which generally have a non-text image centered within the area.

So that we can set an example for best practices, I'm proposing we develop (with @JenFucci's help) a mark logo for Ignite which better suits the app icon format.

Any thoughts are welcome.