add .gitignore
Build template for snippet that users will include in their page

The snippet injects an async script tag pointing to a widget-specific scout
file. The scout file will then asynchronously inject the actual widget code
using a versioned url.

The scout should be served with a max-age equal to the longest amount of time a
user should get stale widget code. The widget code should be served with headers
that tell the browser to cache it forever. See Alex Sexton's explanation at:
bit.ly/Yqmol1.
Add 'build' task, which gets the version and then renders

The version is found in `meta.version`, and is equal to the current commit hash.