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.
Looking at other similar databases that started with a binary-like, then function interface, they eventually moved to an SQL-like syntax, eg cassandra, relegating the binary interface to 'under the hood' status.

SQL-like seems to be the most natural and compatible way for such an interface and greatly simplifies things like making compatible clients that look and are used exactly like any other database client and have API compatibility between them, allowing developers to switch from one database to another with minimal code changes.

Pythons' DB API specification, [PEP-249](http://legacy.python.org/dev/peps/pep-0249/) is a good example here.