Greater use of nicknames to avoid creation of duplicates and in de-duping

Modify the merge duplicates screen to allow user to merge the first name field in one contact into the nickname field of the other, or vice versa. It could be handled like multiple phone numbers are handled now, with a select box for the destination of the merged name.

If the "Include Nickname" option is enabled in search settings, does that apply to duplicate matching searches? If not, it should, or there should be an option in the de-duping rules settings to allow this.

Similarly, when importing data, check imported first name against both first name and nickname before deciding that it is not a duplicate, if the "include nickname" option is set.

In general, treat the nickname as an alternate first name in more situations in order to avoid creation of duplicates and to get more accurate de-duping.