Support for specifying more than one `fname`

[ydirson]

When exploring a project whose entrypoints are scripts, to get the whole we need to draw the deps from all scripts on one graph, and that only seems to be possible when they are part of a module. And even faking modules by creating __init__.py files all over the tree hits its limits when directories contain e.g. dashes, which makes them unsuitable as module names.