Feat/evap upload svc

* made some small improvements to evaporate provider.
* added some meat to the upload service.
* added some basic tests for upload service, other parts of upload not yet tested.
* use of uuid and env in prefixing upload file name
* additional headers for content type, disposition, and privacy
This is not documented, but I do see it in the src, and have requested clarification:
https://github.com/TTLabs/EvaporateJS/issues/53
In the meantime, as I read it this will do what we want, so I am using it to call the promise `reject(msg)`.