Add fractional units representation example

[snowman2]

Follow on from: #248

Example: units: 0.245 m

[davidhassell]

Hi @snowman2 - I'm not sure what is being proposed here, as such units are not supported ...

The Udunits syntax that allows scale factors and offsets to be applied to a unit is not supported by this standard. The application of any scale factors or offsets to data should be indicated by the scale_factor and add_offset attributes. Use of these attributes for data packing, which is their most important application, is discussed in detail in Section 8.1, "Packed Data".

... and since #248 has been closed. Please say if I've missed something!

Thanks,
David

[snowman2]

It works with udunits: pyproj4/pyproj#536 (comment)

>>> from cf_units import Unit
>>> u = Unit("0.5 m")
>>> u.convert(1, "m")
0.5

[JonathanGregory]

It is unclear whether a change is proposed here, so I will close the issue. Feel free to reopen it if there is a question or change to discuss.