Arithmetic with affine units results in rational when integer would suffice

[sostock]

When adding a temperature difference in K to a temperature in °C, one often wants to have the result in °C as well. ContextUnits can be used to achieve this.

julia> x = 5 * ContextUnits(°C, °C)
5 °C

julia> x + 3K
8//1 °C

However, the result has numerical type Rational{Int} even though Int would be just fine. The reason for this is that the + method in this case converts both quantities to K to add them before converting the result back to °C.