fix: return correct buffer object for datastore responses
Add tests for buffer fix
Merge pull request #302 from ryanseys/buffer-fix

fix: return correct buffer object for datastore responses
provide better error messaging - fixes #286
more helpful error message

https://github.com/GoogleCloudPlatform/gcloud-node/pull/303#discussion_r20447351
Merge pull request #303 from stephenplusplus/spp--error-messaging

provide better error messaging - fixes #286
storage: support resumable uploads
add regression test
add some unit tests
lastByteWritten -> numBytesWritten
- 5mb file, + 3 mb file
upgrade mocha + reorder tests
exponential backoff
support resumableThreshold & using simple vs resumable