or evolve, time1, time0
Step the hydro calculation forward to TIME1,
starting with the initial conditions in the
RT, z, and v arrays at time TIME0 (default 0.0
if omitted). The calculation also depends on
the constants M (mass/area/zone) and gammaM1
(gamma-1 for the gamma-law equation of state).
The pressure array p is updated in addition to
the primary state arrays RT, z, and v.
Boundary conditions are specified by setting
either a boundary pressure or a boundary
velocity at each end of the fluid column.
bc0_v - Boundary velocity at z(0), or 
if z(0) has pressure BC.
bc0_p - Boundary pressure beyond z(0).
bc0_time - If bc0_v or bc0_p is an array,
bc0_time is an array of the same
length specifying the corresponding
times for time dependent BCs.
bc0_Z - Acoustic impedance at z(0) if bc0_v
is nil (default is 0).
bcN_v, bcN_p, bcN_time, and bcN_Z have the same
meanings for the z(n_zones) boundary.
The worker routines OutputResults and
TakeStep must be supplied.
interpreted function, defined at i/demo1.i line 119