Spatial and time scale recalculated to actual values.

See owPhysicsConstant.h for detailed comments and example of
calculations for hypothetical 1e+5 particles worm body.  As a result,
particle mass changed from 0.0003 kg to 3.25e-14 kg, simulationScale -
from 4.00e-03 to 2.03e-06, timeStep - from 0.001 s to 4.00e-06 s. This
caused to change a few variables' data type from float to double, to
avoid exceed of data type limits.

Pieces of unused old code removed.