Improve Chronos documentation
Link to extra docs from README, fix typo, describe scaling down
Review feedback
Merge remote-tracking branch 'origin/dev' into api-docs
Fix typo
Merge remote-tracking branch 'origin/api-docs' into api-docs
More liberal use of backticks
Merge pull request #4 from Metaswitch/api-docs

[Reviewer: Andy] API and clustering docs
Don't play replica tennis
Merge pull request #5 from Metaswitch/fix-replica-receipt

Reviewer Rob - Don't play replica tennis
Calculate the start time of a tombstone record in the same way as a newly create timer
Default the start_time to something sensible
Fix up Timer constructor
Merge pull request #9 from Metaswitch/tombstone-start-time

Reviewer Rob - Calculate the start time of a tombstone record in the same way as a newly created timer