Type piracy

[odow]

This method is type piracy:

UnitJuMP.jl/src/units.jl

Lines 178 to 181 in c55366f

	function JuMP.moi_function(func::AbstractVector{<:AbstractJuMPScalar})
	func = [expr(f) for f in func]
	return JuMP.moi_function(func)
	end

The tests fail with JuMP#master because we now return a VectorNonlinearFunction instead of hitting this method.

I don't know what a good solution is. Perhaps we just don't support multi-objective problems with UnitJuMP for now?

[trulsf]

The type piracy arised when trying to support multiobjective optmization combining objectives with and without units. My suggestion is to support only multiobjective optimization when all objectives have units. This should not be too much of a restriction. See pull request #20

[trulsf]

Fixed in version 0.2.2