pre-gyp-publish

Static binary based builds + installs from prebuilt packages are now working. Remaining tasks

- [x] Resolve issue with using aws-sdk-js on v0.8x (https://github.com/aws/aws-sdk-js/pull/321)
- [x] Adjust publish scripts to only attempt binary publishing when commit message contains `[publish binary]` or so

This does not attempt to go beyond no 1 in https://github.com/naturalatlas/node-gdal/issues/36#issuecomment-46931116. We'll follow up this work with no.'s 2 + 3.

cc @rclark @brandonreavis @brianreavis @springmeyer