Expose tiler options via command line

This exposes all the options to tiler (both storage and tiling) to the command line.

I am having an issue with specc'ing the S3 part. It seems as though `Fog.mock!`, required for testing, is not registering when called in a `before` and then running the binary. Perhaps the execution of the `dzt` binary is happening in a different thread?

I left the spec pending for now, I did run this from the command line and verify that it worked.

![screen shot 2014-10-17 at 12 40 09 pm](https://cloud.githubusercontent.com/assets/1457859/4682333/e3043b9e-561b-11e4-9932-895e8452ecdd.png)