Endgame egui

The endgame_egui crate provides helper code for integrating the endgame library with the immediate-mode GUI library egui.

It provides functionality such as:

• Drawing labels.
• Drawing straight and arc arrows.
• Drawing hollow arrows, and hollow self arrows.
• Drawing grid cells.
• Drawing grid tesselations within rectangles.
• Drawing shapes.

Future work

• Some of the helpers in this crate are not particularly specific to the endgame library. In time, it might make sense to look at splitting them out to an independent crate or upstreaming them.
• Overall, the there are a number of improvements in styling that could be supported.
• The code is still quite rough in some places and could be better organized, documented, and optimized.
• Tests using egui's egui_kittest crate could be added.