Fixed h1_summary and h1_summary2 to correctly construct time_bounds values.

h1_summary and h1_summary2 previously used the time_bounds from the last time
value from the last input file when summarizing, suggesting that the field
values were appropriate only over that short time range instead of the complete
time period over which the statistics were calculated. C-LAMP Experiment 1
runs used the previous code, so the time_bounds were incorrect in the
statistical summaries produced. C-LAMP Experiment 2 runs will use this new
code for production of statistical summaries.

Initial commit of post-processing codes for C-LAMP experiments

add_total_fields - modifies model output netCDF files to add fields computed
from fields within the files.

h1_summary - computes means and standard deviations of hourly output netCDF
files, creating two new netCDF files (one for the means and one for the
standard deviations) for each month by hour of day.

h1_summary2 - the same as h1_summary, but it uses more memory to read in more
timeslices at once, so it may be faster on some machines.