adding package.json to enable npm install

added `package.json` to allow installation/management using `npm`

more here https://github.com/npm/npm/issues/6864#issuecomment-65925263
no, I'll ammend those PR's if you like---?

On Sat, Dec 6, 2014 at 8:42 PM, Kenan Yildirim <notifications@github.com>
wrote:

> In package.json:
>
> > @@ -0,0 +1,17 @@
> > +{
> > +  "name": "source-sans-pro",
> > +  "version": "1.0.0",
> > +  "description": "Source Sans Pro is a set of OpenType fonts that have been designed to work well in user interface (UI) environments. In addition to a functional OpenType font, this open source project provides all of the source files that were used to build this OpenType font by using the AFDKO makeotf tool.",
> > +  "main": "index.js",
>
> There's no index.js though?
>
> —
> Reply to this email directly or view it on GitHub
> <https://github.com/adobe-fonts/source-sans-pro/pull/53/files#r21421924>.
>