Bug in noncommonind

[mtfishman]

The function noncommonind(A::ITensor, B::ITensor) for getting a single Index that is unique to A errors:

julia> i = Index(2, "i")
(dim=2|id=902|"i")

julia> A = randomITensor(i, i')
ITensor ord=2 (dim=2|id=902|"i") (dim=2|id=902|"i")'
NDTensors.Dense{Float64,Array{Float64,1}}

julia> B = randomITensor(i', i'')
ITensor ord=2 (dim=2|id=902|"i")' (dim=2|id=902|"i")''
NDTensors.Dense{Float64,Array{Float64,1}}

julia> noncommoninds(A, B)
IndexSet{2} (dim=2|id=902|"i") (dim=2|id=902|"i")'' 

julia> noncommonind(A, B)
ERROR: MethodError: no method matching getfirst(::Array{Index{Int64},1})
Closest candidates are:
  getfirst(::IndexSet) at /home/mfishman/.julia/packages/ITensors/ka3Bv/src/indexset.jl:742
[...]

Also, noncommoninds does not properly accept keyword arguments:

julia> noncommoninds(A, B; plev = 0)
ERROR: MethodError: no method matching symdiff(::IndexSet{2,Index{Int64},Tuple{Index{Int64},Index{Int64}}}, ::IndexSet{2,Index{Int64},Tuple{Index{Int64},Index{Int64}}}; plev=0)
Closest candidates are:
  symdiff(::Any, ::Any...) at abstractset.jl:214 got unsupported keyword argument "plev"