Support for binary deployment

Using [node-pre-gyp](https://github.com/mapbox/node-pre-gyp) this change advances GeoIP to enable users to install the module without a compiler via a binary. This can make GeoIP much easier to install for javascript developers not familiar with native addons and it can make GeoIP much faster to install for devops teams.

Please see the node-pre-gyp docs (https://github.com/mapbox/node-pre-gyp#features) for details of how this works. And [this page](https://github.com/mapbox/node-pre-gyp/wiki/Modules-using-node-pre-gyp) for examples of other apps that are using node-pre-gyp to provide binaries.

Next steps:

  - Decide on hosting location and AWS credentials
  - Help provide first batch of binaries for Linux and OSX
  - Discuss automation for binaries for upcoming releases