Added loading screen

Necessary due to potentially slow load time of wikipedia article string
Set specific font rather than font family

This way, when we get a character that isn't supported by the default
font in the Monospaced family it is simply not displayed, as opposed to
defaulting to another font with different measurements and causing havoc
with the printed world string.
Made FoodStringFetcher remove font-invalid chars

Because where's the fun in eating those blank character boxes?