v0.7.4-beta

• signal arcs now respect gravity (issue #45)
• updates to command line/ node.js code
  • first command line version for rendering sequence charts (using jsdom)
  • command line interface entry points in a separate dir
  • a node module to generate random sequence charts
  • added command line interface entry points to convert abstract syntax trees to other stuff
• additions to debug mode
  • "hard override" coloring which does not respect existing coloring