Create A package.json file so that the plugin can be loaded as an NPM package

With this package.json, I can pull the package direclty into NPM:

```
"dependencies": {
    "jquery": "~2.1.0",
    "hammerjs": "~1.1.2",
    "jRespond": "https://github.com/thejsj/jRespond/tarball/master"
  },
```

If this happens, then another commit would be needed to change the repository field from ```git@github.com:thejsj/jRespond.git``` to ```git@github.com:ten1sevenj/jRespond.git```