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.
I don't understand all this.  the way i see it, we would simply encode all tags in the storage-level seriesname and write to that. for example if you wrote to `cpu_load` with tags `["dataCenter/USWest/host/serverA.influxdb.com"]` why not just write to a series called `cpu_load__tags:dataCenter/USWest/host/serverA.influxdb.com` ?
and that series would be use when you query cpu_load, or cpu_load where datacenter=USWest or any of the queries it applies to.