Add TODOs

TODO.txt

@@ -1,5 +1,13 @@
 =========== GENERAL ==============
 
+- Create a physics test map.
+- Unstuck idea: make the body non-rotating for a while?
+- Map4: fix top bottom corner, making the curve is too hard -- either add ramps
+  on wall or shift the down ramp further.
+- CP gets often missed, would be cool to increase its radius, but also hard.
+  We would have to be checking 8 cells instead of one, but even then issues
+  would appear with multiple CPs next to each other (returned CP_TAKEN event).
+  Maybe at least make the CP model smaller? (make the diamond diagonal)
 - Fix weird reversing.
 - Try doing the bouncy car body? Just keep a point and its velocity, change
   its velocity by a proportion of car's velocity change (this minus prev.