Merge pull request nameko#494 from nameko/v2.8.1rc

v2.8.1rc

Merge pull request nameko#489 from nameko/v2.8.0-rc

v2.8.0 rc

Merge pull request nameko#480 from nameko/v2.7.0-rc

v2.7.0-rc

Merge pull request nameko#434 from nameko/v2.6.0-rc

v2.6.0 rc

Merge pull request nameko#433 from nameko/v2.5.4-rc

v2.5.4 rc

Merge pull request nameko#419 from davidszotten/bump_prefetch

Bump prefetch

Merge pull request nameko#415 from nameko/v2.5.2-rc

v2.5.2 rc

Merge pull request nameko#396 from nameko/v2.5.1-rc

v2.5.1 rc

Merge pull request nameko#391 from nameko/v2.5.0-rc

v2.5.0-rc

Merge pull request nameko#383 from mattbennett/consumer-heartbeats

enable heartbeat (by default) for queueconsumer