edit about-extended.md; copy that and about.md to README.md
Merge branch 'master' of https://github.com/jennybc/r-graph-catalog

# By Joanna Zhao
# Via Joanna Zhao
* 'master' of https://github.com/jennybc/r-graph-catalog:
  Change link to r-graph-catalog repository
  Generate figure pngs, READMEs, and copy to r-graph-catalog app
  Create target for syncing to r-graph-catalog shiny app
  Create thumb and fig dirs in app if they don't exist