Merge tag '1.6.0' into develop

1.6.0
Tweaks to schedule
Added JSON handlers for Interval
Updated Metrics and Jetty to latest versions
Added JMX reporting to metrics
Tidy-ups for new Metrics
Updated configurations
Merge pull request #13 from wealdtech/feature/schedule

Schedules.
Added TriVal
Tidied up implementation of clear()
Added GuavaUtils
Merge pull request #14 from wealdtech/feature/misc

Misc.
Merge branch 'release/1.7.0'
Release of 1.7.0