Revert "Merge branch 'player-speed' into 'next'"

This reverts merge request !1309 (merged). We agreed internally that this is the best solution, for reasons including not wanting to invoke compensating hacks (like those in !1411 (closed) and !1414 (closed)) or risking other undiscovered side effects of the change. We'll probably look at properly deprecating P_AproxDistance in a future major release.

Resolves #466 (closed) and #471 (closed).