In the case that there were more than one comment blocks preceding a block of
code, the visitor was only attaching the first comment. Really what we
should do is to attach the last comment before the code block.
simplify:
- use same html file for dart and JS
- build benchmarks automatically when doing `gulp build`
- centralize configuration
modularize:
- move all build tasks into separate node.js modules under
`tools/build`.
changes:
- the `build` folder is now the `dist` folder
Closes#284