Brand asset allocation/consolidation

With main-net approaching, undoubtedly more will be reaching out for grin brand assets—I've already seen this in a few places. Perhaps we should consider taking the following steps:

• Consolidating all brand assets into one document (logos, color values, exchange symbol, etc.)
• Adding this document to grin-tech.org
• Creating a dedicated GitHub repository for the assets (they are currently hidden at mimblewimble/site/assets/images)

Media outlets and designers can then be given a definitive direction.