Fix :style / GraSS regressions

[oskarhane]

• Output :style in the form of GraSS and not JSON
• Download / Export GraSS from :style frame
• Reset style from :style frame in bottom right corner

node {
  diameter: 50px;
  color: #A5ABB6;
  border-color: #9AA1AC;
  border-width: 2px;
  text-color-internal: #FFFFFF;
  font-size: 10px;
}
relationship {
  color: #A5ABB6;
  shaft-width: 1px;
  font-size: 8px;
  padding: 3px;
  text-color-external: #000000;
  text-color-internal: #FFFFFF;
  caption: "<type>";
}
node.Movie {
  color: #68BDF6;
  border-color: #5CA8DB;
  text-color-internal: #FFFFFF;
  caption: "{title}";
}