Implemented contact.merge(source)

The contact.merge(source) method will mostly merge source embeds without
duplicates into contact. It will also merge bio if contact.bio is blank.
Implemented person.merge(source)

Method person.merge(source) adds merging last_name, first_name, title and
company_id to contact.merge(source).
Implemented company.merge(source)

Method company.merge(source) reassigns source.people to company.people.
Implemented ui for company merge

The user interface for merging two companies. Step one, find the
company needing to be merged. Step two, edit company. Step three, click
Merge this company. Step four, find target company using form. Step
five, merge companies.