Upgrading to latest source

No longer do you need to download a the new ISO build to upgrade the source code. Simply follow these steps;

• WARNING Do not perform an update unless we release a new version. Interim code updates from us are not full version updates. We will attach a new version release note to the github readme when there is a new version. Only then should you update.
• Make sure the machine is connected to the internet.
• Execute yum check-update then yum update nighthawk. This will get you the latest mappings/source code to operate nighthawk at the latest version.
• If mappings have changed you will need to reindex your data, this is explained in the Reindexing data wiki article.

We wanted it to be straight forward and easy for anyone running an existing system to get the latest features and bug fixes without having to download a new ISO and ingest collections all over again.