tree-differ:
- export both TreeDiffer and DiffResult interface
diffing-broccoli-plugin:
- factory class for wrapping DiffingBroccoliPlugins and turning them into BroccoliTrees
broccoli-dest-copy:
- refactor into DiffingBroccoliPlugin
broccoli-traceur:
- refactor into DiffingBroccoliPlugin
Previously, karma used a custom preprocessor. Instead, have karma
run built dart from the `dist` folder and use gulp and broccoli
to watch for changes.