Many changes while working on Daly Uncleared data.
templates/L1.txt:
 - added "time_zone" global attribute
nc2xls.py:
 - added DateTime_UTC to list of variables not written to Excel
   file
pysolar.py:
 - added to OzFluxQC scripts, taken from Pysolar (http://pysolar.org/)
 - used to calculate synthetic downwelling shortwave radiation
   from UTC datetime and location
qcio.py, qcls.py, qcplot.py, qcts.py, qcutils.py:
 - UTC datetime now calculated and stored in data structure
 - synthetic Fsd (Fsd_syn) calculated and stored in data
   structure
quickcheck.py:
 - if there are gaps in Fsd and if Fsd_syn exists then use
   Fsd_syn to fill the gaps in Fsd to allow day/night text
   (Fsd>10) to be applied