Refactor api

Here are some of my ideas around refactoring how InfluxDB's API works. The key learning here is that people have been using string columns like tags and it leads to bad performance.

My goal here is to make that the default and to expose an API that is more purpose built around the metrics/time series use case as opposed to the more general purpose SQL.

Please comment on the individual lines of [influx_api_v2.md](https://github.com/influxdb/influxdb/blob/refactor-api/influx_api_v2.md) for focused feedback. Or leave comments in the thread for more general thoughts.

I'm also very interested in hearing about specific use cases. Have I captured everything here? What have I left out? I know this can't encompass everything, but my hope is that it creates a clean foundation that we can easily expand upon.

@jvshahid, @toddboom, @benbjohnson, @dgnorton, @otoolep: please to review.
This is important to my use case. I am making an application to detect anomalies in time series data. The end user of my application will define the time intervals they wish to be used as windows for anomaly detection. I'll then use those windows to create a set of retention policies to down sample the data appropriately.  I do not want to burden my end user with the complexities of shard spaces and retention polcies, being able to programatically choose the optimal retention policy and even change at a later date is very nice.