resolves #666 Adding Therms (US)/Hour

[ohshazbot]

• Adds therms/hour

This was effectively done by mashing together BTU_IT-PER-HOUR with THM_US since I'm not that intimately familiar with everything here. Please let me know if I missed anything and I'll correct it.

[ohshazbot]

Cool, I went ahead and:

• Updated the conversion rate (good catch, I neglected that base units weren't hours)
• Attempted to write a description directly related to it
• removed qudt:definedUnitOfSystem
• replaced qudt:uneceCommonCode with "THR" (it doesn't look like there's a ton of reason behind most of these identifiers?

[ohshazbot]

Oh, I didn't. There were so many in the spec that didn't seem to actually be defined, I was under the impression that it was supposed to be user defined if not previously specced. Though looking at that link, I see that Therm (n72) does have a common code (TD), so it does appear there is some drift

[ohshazbot]

But looking at the official list, it looks as though they have not given therm/hr a common code. There's an official PDF here https://unece.org/DAM/trans/bcf/eTIR/documents/CodeLists0_4.pdf and what looks like an xlsx via primary and additional annexes available here https://unece.org/code-list-recommendations#accordion_9 in case you want to do somewhat better lookups

[steveraysteveray]

If there is no UNECE code to be found, we just omit that triple. I will get rid of it next time I do an update.