Minor refactor, update Bobfile format, logs over http

Addresses:

* https://github.com/modcloth/docker-builder/issues/66 - fix parser test failures
* https://github.com/modcloth/docker-builder/issues/8 - add versioning to Bobfiles, update Bobfile format
* https://github.com/modcloth/docker-builder/issues/53 - adding http endpoint for viewing logs per 
* https://github.com/modcloth/docker-builder/issues/27 - indicate how long each build took (via http logs)

Not ready until:
- [ ] maybe tests for logging endpoints
- [ ] documentation for log endpoints

Make semi-backwards-incompatible changes to the `Bobfile` format.  Addresses a [change in Go 1.3](http://golang.org/doc/go1.3#map).
Not sure how I feel about only keeping the logs around for such a small period of time, but this is a good start.