v0.7.0

Added

• New flag --description-file to generate a description file of the Graph Nodes
  (Issue #178)
• graphviz is now in the Docker image so no need of external tools to generate the graph by @agalazis
  (PR #221)

Changed

• Updated the tfdocs version
  (PR #198)
• The generate command will now print more suitable node names if alternative-node-names flag is used.
  It's turned off by default
  (Issue #230)