rewrote whole node backend to fit new spec

* supports new API spec
* Jobs have been abstracted into an object and are self managing while retaining asynchronousness
* Jobs maintain status and stage states
* Jobs destroy themselves and clean up when finished
* regularly posts state with correct varying format to Rails
* jobs have random processing speeds and varying bytes processed

Routes:
```
GET /
```
confirms that server is alive

```
POST /transcode
```
takes a ```job_id``` for the unique job identifier and ```size``` for the total size of the file

```
DELETE /transcode/:job_id
```
destroys job with passed job_id before job is finished