Make LinearCombination support specifying axis key as the dims?

[nicoleepp]

does this also work if passing in the axis key? e.g. foo, bar?

Originally posted by @glennmoy in #8 (comment)

[nicoleepp]

We are leaving this for later, as eachslice is lacking axisnames support and it’s not going to be expected that Transforms supports it

See JuliaArrays/AxisArrays.jl#7

[nicoleepp]

Related to #20

[glennmoy]

stale issue - we won't be directly support Axis names in this package