Publish initial release to npm

[thisisdano]

If we want folks to try out this gulp package, we should ask them to use npm for downloads instead of directly from github.

[kdimatteo]

I was also thinking this as I read the README. Is there a namespace this should be published under?

[thisisdano]

We'll be doing this, but via uswds/uswds-compile#1 in uswds-compile. When complete and merged, we'll publish to @uswds/compile.