Remove the old series cruft from database and metastore
Update Database and Metastore to keep series info

* Change database to keep all data under a bucket in bolt
* Subbucket under the database to keep tagbytes to ids
* Subbucket under the database to keep ids to tag values
Add Fields to Measurement.

* Add Field
* Changes series on meta to measurements for consistency
* Update metastore to store serialized Series object instead of tags
Fix wrong lock on create series, rename Series to Measurements for consistency
Fix build, cleanup database measurements test.
Merge pull request #1201 from influxdb/tag-index

Tag index