package name?

I'm not sure what a "base type" is in general, so I'm not thrilled with the package name.  (It sounds like it has something to do with supertypes and inheritance.)

DimensionlessRealType.jl, exporting `dimensionlessreal(x::Number)` and `dimensionlessreal(T::Type{<:Number})` would make more sense to me, and gives a more precise indication of what the package actually does.