Revision 166

Split ppm3d.f into files containing a single procedure.

Factorized computations of filtering matrices into a procedure
inifilr_hemisph. Had then to change the matrices from allocatable to
pointer and from customized lower bound to lower bound 1. The change
in lower bounds does not matter because the matrices are only used as
a whole as actual arguments.

Also, in infilr, instead of finding jfilt[ns][uv] from approximately
jjm /2, start at index j1 that corresponds to the equator. This is not
the same if there is a zoom in latitude.

Also, the test (rlamda(modfrst[ns][uv](j)) * cos(rlat[uv](j)) < 1) in
the loops on filtered latitudes is not useful now that we start from
j1: it is necessarily true. See notes.

Just encapsulated lwvn into a module and removed unused argument ktraer.