Revision 177

Removed the option to use PPM3D advection schemes. This looks really
bugged. In particular, in ppm3d:
     do i=1,IMR*JMR
	CRY(i,2) = DTDY*V(i,1,k)
     end do
while cry is declared as:
real CRY(IMR,JNP)
and:
jmr = jnp - 1

Also removed options for Slopes and Prather advection schemes. This
does not look functional. It seems it needs tracers inside tracers.

Also removed allowed values 1 and 2 for iadv in iniadvtrac. These are
not implemented in advtrac.

With the removal of PPM3D, there is no longer any need to distinguish
between hadv and vadv in iniadvtrac.