Email formatting improvements

DO NOT MERGE YET
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Fixes **still needed**:
* Human-readable description (need correct reference to Michael's formatting code)
* Need location of config entry for website URL so we don't hard-code it

Fixes in this commit:
* Removed sysname from subject line (added to end of message body in case it's needed)
* Conditional formatting of "Event Type:" or "Event 1 Type" depending if there are multiple events in an email
* "ts_created" is now "Date & Time"
* Removed "full dictionary" listing
* Changed unsubscribe information as per Lynn's suggestion