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.
ok, I'll have to write up a bit more on sharding since there's some confusion here. There's still a split across the cluster to balance metrics data across all machines. It's just that a single series will be on a single shard for a given period of time. In a system with millions of series (common for a cluster) this works well as a method to balance the data.

It only presents a problem for series with irregular periods and a very high volume. Think event streams. Measurements series (like sensors, servers, devops, etc) don't present a problem here.