units

As per angularsen/UnitsNet#328 (comment)

Having a set of tests to validate that the correct abbreviation notations and symbols are used would be helpful, as we have seen from before that discrepancies tend to creep in over time.

See #328 for the (currently work in progress) guideline, go through the comments and identify what tests to write for the guid

The documentation says this "Even though mp-units library does not implement any Linear Algebra types it is generic enough to be used with other Linear Algebra libraries existing on the market.". A set of examples using Eigen would be helpful. Blaze would probably be good too, but personally I don't use it so it's a lower priority for me.

It came up in #41 that it would be nice to have functions like abs(), sqrt(), etc. implemented on $System<f64, U> (and friends) directly, and not just through traits, so that they could be called without the traits in scope.

No Unit found is not descriptive at all.

We should at least make that error message more clear for cases like:

• "75kg" instead of "75 kg"

Our assumption for parsing a compound quantity is that there will be a space character between the value and the unit

Feature Request: weather! I'd like to type "weather in Hiroshima" and have some sort of result. Current, high, low, humidity and precipitation chance would be nice.