Handle 'primary' contact information when manually merging contacts

When merging contacts, and adding a new address, it is not possible to specify which one should be primary.

So currently.

Duplicate (record to delete)
Work address (PRIMARY)

Master (record to keep)
Home address (PRIMARY)

[Choose to 'migrate' the work address to the master record when merging]

Result
Home address (PRIMARY)
Work address

ie: The 'primary' address on the master record stays primary.

This is reasonable default behaviour, however you may wish to specify a different address to be primary.

Proposed solution:

Add checkboxes to the 'manual' merge screen which allows you to 'Set as primary' any of the addresses, phone numbers or email addresses that are being 'migrated'.