Add tests to ensure PR follows contribution guideline

[angularsen]

As per https://github.com/angularsen/UnitsNet/issues/328#issuecomment-346925537

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 guideline we have arrived at so far. This will evolve over time, but we have enough to start with already.

Update #328 description with the complete list of rules that you gather from the comments, and mark those that are automated by tests with an asterisk and a footnote explaining that below. Then whenever we add new rules to the guideline, we will make it a routine to both update the issue description and add a test case (if feasible).