Issue tracking workflow

HPCC-Platform issue tracking has been moved from GitHub to a Jira-based system. The Jira issue tracker is much more powerful and configurable than the GitHub one, and should allow us to track and manage what is fixed for what version by what developer much more effectively.

We will still use the GitHub pull-request mechanism (at least for the time-being) for reviewing and accepting contributions.

Integration between GitHub and Jira is a little lacking compared to the integration within GitHub - in particular there is no mechanism for automatically closing an issue when a commit is merged into the github repository (though the issue WILL be updated to reference the commit, if the HPCC-nnnnn tag is properly used in the git commit comment).

The workflow in Jira should look like this:

1. A new issue is created, and goes into the 'New' state.
2. New issues are triaged regularly to see if any are urgent (and need flagging for immediate action) or can be trivially closed (duplicates or spam). Generally, they will be 'Accepted' and move into the 'Open' state
3. An issue that a developer is actively working on is moved into the 'Active' state.
4. When a pull-request is ready, selecting the 'Attach Pull Request' in Jira will allow a reference (URL) for the pull to be entered, and the issue moves into the 'Merge pending' state
5. When the pull request is accepted, the issue moves into the 'Resolved' state. If the pull request is not accepted, the issue can be moved back into the active state.
6. Once testing is complete and/or the reporter is happy with the resolution (including docs and tests where necessary), the issue may be moved into the 'Closed' state

It will be helpful when issuing a pull request if you can remember to update the corresponding issue in Jira to 'Merge pending' state. Pull requests without a corresponding issue will not normally be accepted (so create the issue first!)