Feature freeze and documentation

Most of the documentation is ready. Most of the KairosDB features are implemented.

Get tagnames and tagvalues

Merge pull request #20 from kstrempel/move-to-0.2.3

Forward to 0.2.3

Adds list and delete metrics

Merge pull request #15 from kstrempel/version-0.2.2

Updates README and Cargo version

v0.2.0: Merge pull request #10 from kstrempel/adding-module-documentation

Adding module documentation