Add setup instructions for various OS's

[jbeezley]

The dependency on GDAL 2 will likely be a roadblock for many users. It would be helpful to provide instructions for a few common OS's. I started this by adding a wiki page for mac OS. I don't know if we want to move this to the README or not, but I just wanted to make a note of what I did to get it running.

[danlamanna]

Well ansible/circle handle it for Ubuntu, that plus Mac OS covers it pretty well I think.

[jbeezley]

If we are going to recommend ansible for Ubuntu, we should provide a command for local provisioning. Also, it looks like the ansible deployment hasn't yet been updated to install gdal 2. Could we use that for provisioning on circle to keep it up to date?

[kotfic]

A few things:

1. Using the ansible role to deploy to circle sounds like a good idea. I have created an issue.
2. Because of the complexity of deploying and configuratin gdal/mapnik I am hoping that the primary way people will test/experiment with this technology will be through docker.
   1. This is blocking on ktile integration (so we can drop geoserver as the default tile server) and have the whole thing run inside a single process (the jupyter notebook process).
   2. Documentation as you suggest will still be important but it should be developer focused rather than user focused and is (for now) a relatively low priority