All love.graphics state settings are now set to their default by a
single call of love.graphics.reset() when the love.graphics module is
loaded. This means the default value for each love.graphics setter is
now located in the corresponding set function.
The default font is now created as a real lua object and added to the
lua registry under the address of its struct pointer. The
love.graphics.getFont() function can now be used to retrieve the default
font.
