* Make all hitboxes rectangles
* Add sprite-based hitboxes for attacks, keep the original ones only for
map wall collisions
* Reorganize and rename animations
* Separate player movement and swing animation for the AoE
* Define more-useful primitives that are fixed in a coordinate system
* Provide conversion functions to and from integers as we need it
occasionally and it's better to have it at hand
* Add geometric functions (scale/translate)