Comments added when an issue is progressed or resolved are linked with the duration worked and not the issue.

Fixes headsupdev.org issue:agile:34
Renamed CreateComment.childWillConsumeComment() to willChildConsumeComment().
Comments are only added to DurationWorked if the additional time is non-zero.
Merge pull request #4 from CharlesHarley/duration_worked_comment

Link comment with duration worked