Naive parser for graphviz/dot formatting options. TBD: method to add/replace format options, rather than exposing self.fmt

ordered set implementation linked from StackOverflow http://code.activestate.com/recipes/576694/ https://stackoverflow.com/questions/1653970/d

Distinguished from a Regular Edge, by its Dot language format string.

Finds terraform/hcl files (*.tf) in CWD or a supplied directory, parses them with pyhcl, and exposes the configuration via self.config.

Stands in for multiple DotNodes at the same module depth...

A bit of a hack to simplify conditionals with multiple regexes. e.g. if (match = re.match(pattern, ...)) { match.groupdict(...

Sometimes we want to hide edges, and sometimes we want to add edges in order to influence layout.