Check for Duplicate Contacts from Add/Edit Form

Add new form button - "Check for Matching Contact(s)" - to Edit.php/tpl - at lower left of 'Name and Greeting' fieldset. Button posts currently entered form values to dupe checking function.

If no matches, returns status - "No matching contacts found."

If one or more matches, returns listing of dupe suspects in table - including display_name, city, state, country, email as available.

User instructions should include: "If this is NOT a duplicate of the contacts listed above, please modify your input or add additional data which will differentiate this record from the other listed contacts."

NOTE: This could be a good candidate for implementation via Ajax - since we could invoke a server-side dupe check function w/o actually submitting the entire form.