* implement player spellcard declarations on bomb
* stagedraw: move "bottom text" to a separate (higher) layer
* update boss spell declaration effect
* import afensorm's character portrait art
* improve dialog visuals
* acknowledge afensorm in credits and COPYING
* 'alphamap' functionality; effects for wriggle and youmu portraits
* update afens art
* add cirno alphamap
* dialog: draw active speaker above other other
* charselect: use r_draw_sprite