Check datatypes, instruments, and platforms

[Bobfrat]

From @mbiddle-nodc:

We also have a response for datatypes (https://www.nodc.noaa.gov/cgi-bin/OAS/lookup?format=xml;table=datatypes) which would be the terms in the ncei_name attribute of the geophysical variable.

Similarly for instruments (https://www.nodc.noaa.gov/cgi-bin/OAS/lookup?format=xml;table=insttypes) and platforms (https://www.nodc.noaa.gov/cgi-bin/OAS/lookup?format=xml;table=platforms).

[MathewBiddle]

Stand-by on these checks... A can of worms has opened over here and we need to make a decision.

[MathewBiddle]

This has turned into a larger discussion within NCEI about the use of ncei_name/nodc_name/sea_name. For now, I think our best route is making the weight on these checks as small as possible.

The sea_name check can use the xml file at http://www.nodc.noaa.gov/General/NODC-Archive/seanames.xml.

For ncei_name/ncei_code, we haven't released our other tables, which contain the vocabulary, to the public yet. I would recommend a simple check for existence. If it exists, good. If not, make a note that it's missing.

[Bobfrat]

@mbiddle-nodc Sounds good. The existence check is already in place. We'll wait until the names are released to the public to check the vocabulary.