Revision 178

Moved variables date0, deltat, datasz_max, ncvar_ids, point, buff_pos,
buffer, regular from module histcom_var to modules where they are
defined.

Removed procedure ioipslmpp, useless for a sequential program.

Added argument datasz_max to histwrite_real (to avoid circular
dependency with histwrite).

Removed useless variables and computations everywhere.

Changed real litteral constants from default kind to double precision
in lwb, lwu, lwvn, sw1s, swtt, swtt1, swu.

Removed unused arguments: paer of sw, sw1s, sw2s, swclr; pcldsw of
sw1s, sw2s; pdsig, prayl of swr; co2_ppm of clmain, clqh; tsol of
transp_lay; nsrf of screenp; kcrit and kknu of gwstress; pstd of
orosetup.

Added output of relative humidity.