Update section 4 (CF-1.7)

[RosalynHatcher]

Additional checks:

4.3 Vertical (height or depth) Coordinate
Recommendations:

• The positive attribute should be consistent with the sign convention implied by the definition of the standard_name, if both are provided.

4.3.3 Parameterized Vertical Coordinate
Requirements:

• The formula_terms attribute is only allowed on a coordinate variable which has a standard_name listed in Appendix C.

• The type of the formula_terms attribute is a string whose value is list of blank separated word pairs in the form term: var. The legal values term are contained in Appendix C for each valid standard_name. The values of var must be variables that exist in the file.

• Where indicated by the appropriate definition in Appendix D, the standard_name attributes of variables named by the formula_terms attribute must be consistent with the standard_name of the coordinate variable it is attached to, according to the appropriate definition in Appendix D.

• The computed_standard_name attribute is only allowed on a coordinate variable which has a formula_terms attribute.

• The computed_standard_name attribute is a string whose value must be consistent with the standard_name of the coordinate variable it is attached to, and in some cases also with the standard_name attributes of variables named by the formula_terms attribute, according to the appropriate definition in Appendix D.

[RosalynHatcher]

Section 4.3.2 has been separated into 2 sections - 4.3.2 and 4.3.3. The first 2 items in 4.3.3 list above used to be in 4.3.2. Updated section code accordingly in chkFormulaTerms routine.