Test on recent Ruby releases
[FEATURE] Provide timestamps of events as `#timestamp`, `#receipt_time` and `#best_time`
[CS] Better error when failing to parse AGI results
[DOC] Changelog entries
[UPDATE] Bump to 2.2.0
Updated rubies for CI

1.9.2 is no longer supported
Merge branch 'release/2.2.0'
Merge remote-tracking branch 'adhearsion_master/master'