Changed h1_summary/h1_summary2 to write a timestamp that is centered on the time bounds.

h1_summary and h1_summary2 previously wrote out a timestamp representing the
last time entry in the last file to be summarized. Now, to follow convention,
the timestamp is recomputed as the mean of the first and last time_bounds,
where the first time_bounds value is the first value from the first time
entry in the first file and the last time_bounds is the second value from
the last time entry in the last file.

 #!/bin/bash

 source /opt/modules/modules/init/bash

 # for robin

 #module unload PrgEnv

 ##module load pgi/6.1

 ##module load netcdf_pgi/3.6.1

 #module load netcdf_gcc/3.6.1

 # for phoenix

 module purge

 module load open

 module load PrgEnv.5407

 module unload mpt

 module load mpt.2.4.0.6

 module load pbs

 module load netcdf/3.5.1_r4

 #

 module list