Try to detect player traces going through a change in fluid medium
such as water/air or water/glass, and block facial recognition
through it.
Specifically allow air-into-glass transitions, or into any other
medium otherwise clear enough to allow sunlight to propagate.
Standardize the "play a sound for everybody except the player who
is already playing it client-locally" logic into one place.
Fix failure to correctly detect tool speeds for some things, i.e.
when the player is using a tool but the capability used on a node
is actually inherited from the hand.
Note that this may allow pummeling with wrong tools (e.g. repacking
soils with spades) along with accompanying inappropriate tool wear,
but this should be minor and avoidable, and can be fixed later...
