fix: response error encoder only if response not been written yet

fix: response error encoder only if response not been written yet

chore: disable err logging when encoding transport response

Merge pull request #1 from benjamin99/master

Feature: add interface: LastModifiedChecker to transport/http

Add ETagChecker to http transport

Remove default AlwaysSample from http and grpc transport tracing

Rename package

rename pkg

Use newest Go releases for testing (go-kit#757)

rm ROADMAP.md