IMOS template - add standard variable attributes #40

The IMOS template should automatically include standard variable attributes (as specified by the IMOS NetCDF Conventions) for any variable included in a dataset. Attributes to include are:

• standard_name (where applicable)
• long_name
• units
• _FillValue
• valid_min, valid_max
• reference_datum (where applicable)
• positive (for vertical coordinates)

(see laso imosParameters.txt in imos-toolbox)