Change logo to Pfaffmanager--no camelcase

Get @keegan to change the top logo to Pfaffmanager rather than PfaffManager (the capital M seemed like a good idea, but I decided I don’t like it).

Also, remove the shading from the bottom. Also seemed like a good idea, but it ends up looking more like jpeg aliasing rather than something intentional.

See about making a wireframe, or no background, version for the favicon.