Extract all To: and CC: addresses from email header

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I have a number of teams moving into OSvC incident handling from Outlook/Exchange emails.  They are really excited about being able to know how many transactions they are handling, SLA metrics, etc. - which they couldn't do with emails.  They have some interesting process requirements which require knowing the TO and CC addresses in the email header, which we so.  I found a couple of posts about using a regex to detect email addresses, but after examining a bunch of emails with real data, including "name in quotes" <email in angle brackets>, To and CC sections spanning multiple lines and