Add icons

[ryankurte]

Open Iconic project has a bunch of icons that would be perfect.
https://useiconic.com/open/

Probably need to be able to selectively include (or at least prompt the optimizer to remove unused) rather than wasting flash on unused icons.

Font pipeline from issue #1 would help with automating the transfer.

[ryankurte]

Need to work out how to wrap icon data.
Best way is probably to provide a helper that configures a sprite structure for a given icon (and icon scale). That way there isn't the overhead of describing an entire sprite for each icon, and the compiler should be able to optimize out unused icons.

[jockm]

Alternately you could treat icons as an application specific font