Don't always perform a Wagner build before a network build

[recursion-ninja]

If we specify a network build, build a network by adding edges to the given topology.

If we specify a Wagner (tree) build, build a tree by tossing the topology and starting over.

[recursion-ninja]

I have updated the build command to use the input graph, not a new Wagner build, as the base object to add edges to when performing a network build. For the old functionality of performing a Wagner build then a network build, simple invoke the following two commands:

build(tree)
build(network)