complete methods:

- [x] createComment
- [x] getComments
- [x] getLabels
I know Jira doesn't support actual labels, but does it support types? like bug,task,enhancement. and priority.
This how I solved this in BitBucket https://github.com/gushphp/gush-bitbucket-adapter/blob/master/src/BitbucketIssueTracker.php#L359