WITSML Units Support

[slkinnison]

Add support for WITSML units as defined here: http://w3.energistics.org/uom/poscUnits22.xml

[keilw]

It seems a Unit Catalog, somewhat similar to UCUM. we'll consider it, thanks. If you wish to contribute, let us know. Unlike API, RI or TCK pretty much everything else is open to participants. Maybe starting with PL. we're happy to invite new adopters as a next step.

[keilw]

Actually the main system or catalog seems POSC. @slkinnison Are you able to help with that? I would not put it under uom-common, because it seems less common. Actually https://github.com/unitsofmeasurement/uom-domain could be the better place, because this is the collection of "vertical" domain-specific modules and standard catalogs. http://www.energistics.org/ defines standards for the energy/oil sector, so we'd have to ask them if their standards e.g. the mentioned XML are free to use or governed by any commercial license with royalties (e.g. ISO does)

Another link http://w3.energistics.org/uom/poscUnitsClasses22.xml to the underlying XML file (still same version it seems)

[keilw]

Not sure, if it's Open Source, but there is at least one Java library http://jwitsml.org/ for WITSML.
It is according to http://www.energistics.org/drilling-completions-interventions/for-developers/open-source-java-witsml-client-sdk
and
https://sourceforge.net/projects/witsml/