More images to convert to Vector

[Penaz91]

Some images could benefit from vector conversion, those are usually images that represent diagrams.

Follows a list of those I think can be redone as vector:

• [x] AI/dijkstra_path.png
• [x] AI/euclidean_distance.png
• [x] AI/greedy_best_first_path.png
• [x] AI/manhattan_distance.png (remove second example too)
• [x] AI/pathfinding_heuristics.png
• [x] AI/pathfinding_reference.png
• [x] AI/wandering_1.png
• [x] AI/wandering_2.png
• [x] AI/wandering_broken.png
• [x] algorithms/bintree_1...6.png
• [ ] algorithms/diamond_square_1...5.png
• [x] algorithms/eller_1...7.png
• [x] algorithms/kruskal_1...6.png
• [x] algorithms/RDFS_1...4.png
• [x] algorithms/recursive_division_1...6.png
• [x] developing_mechanics/coyote_time.png
• [x] developing_mechanics/enhanced_gravity_jump_plot.png
• [x] developing_mechanics/jump_buffering.png
• [x] developing_mechanics/physics_accurate_jump_plot.png
• [x] developing_mechanics/timed_jumps.png
• [x] game_design/secret_in_secret.png
• [x] project_ideas/tic_tac_toe.png
• [x] project_ideas/breakout_bias.png

[Penaz91]

secret_in_secret.png only went through redrawing, the svg version is complex and weighs over 600k, against the 100-ish of the PNG version.

[Penaz91]

recursive_division_6.png has been kept as-is for now. Too much effort redrawing it in svg for now

[Penaz91]

Done, may convert more images as time goes on, but this should be enough for now