List done tasks in visualizer

List done tasks in visualizer as well as upstream failed and failed.
Small fix to JS indentation
Show "Dependency graph" button for done tasks

Show "Dependency graph" not "Show error trace" button for done tasks in
task list.
Render dependency graph in Firefox

Dependency graph currently renders in Chrome but not Firefox, seemingly
because the SVG viewbox is not being scaled to cover the graph. Set
viewBox, height, and preserveAspectRatio attributes on the SVG element
to show the dependency graphs in Firefox.
Merge remote-tracking branch 'visualdna-external/list_done_tasks' into visualdna_hackday_2013-06-19
Merge remote-tracking branch 'visualdna-external/render_dependency_graph_in_firefox' into visualdna_hackday_2013-06-19