Redrew all of the not-low-poly pipe-related models

to higher quality.  Way more polys than before, but
without a measurable drop in FPS.

Also tweaked the textures for the pump and flow
sensor, and tweaked the low-poly models for them,
so that low-poly models use a different part of
the texture for the "light" on the side (allows
the higher-poly models to just put a glow there
and use a raised dome for the actual light).

Also fixed a Z-fighting issue with the grating on
the bottom of the pump (both versions)

models/pipeworks_flow_sensor_lowpoly.obj

@@ -65,10 +65,10 @@ vt 0.2647 0.9902
 vt 0.2647 0.7549
 vt 0.5000 0.7549
 vt 0.5000 0.9902
-vt 0.5196 0.7549
-vt 0.8333 0.7549
-vt 0.8333 0.9902
-vt 0.5196 0.9902
+vt 0.0098 0.5000
+vt 0.3235 0.5000
+vt 0.3235 0.7353
+vt 0.0098 0.7353
 vt 0.2451 0.7549
 vt 0.2451 0.9902
 vt 0.0098 0.9902