Conversion from a SimpleWeightedGraph incorrectly swaps edge weights #56
Description
Example:
julia> using SimpleWeightedGraphs
julia> g = SimpleWeightedDiGraph([1], [2], [1])
{2, 1} directed simple Int64 graph with Int64 weights
julia> SimpleWeightedGraphs.get_weight(g, 1, 2)
1
julia> SimpleWeightedGraphs.get_weight(g, 2, 1)
0
julia> metis_g = Metis.graph(g)
ERROR: weights must be positive integers, got weight 0 for edge (2, 1)
...The error comes from this line:
Line 25 in 5eea928
Which should be get_weight(G, j, i).