Bump version to 0.7.1

Add a TODO for histogram support

Upgrade deps to latest versions

Bump version to 0.7

Name the thread which drains the channel regularly

Bump version to 0.6

Name the HTTP server threaddiff

Bump version to 0.5

Unit test the new min()/max() functions

Add Metric.{min,max}()

Refactor the http spawning functions a bit

Inline init_state() and fix some comments

Remove port from State

Remove existing_server_port()

Update the docs

README: Mention query() as an alternative to HTTP

Add a unit test

README: Update line-count

Add a query() function

Get rid of mio dependency