Add levels

[OleksiyRudenko]

E.g. #50 can be a next level as well as a CatWoman, friends.

[OleksiyRudenko]

level x. Add a friend
level x+1. Add friends mutually
level y. Real friend, not just a name
level z. List friends' names+lastNames if any

[OleksiyRudenko]

Add/change following properties (should also be a part of output):

• Humans|Pets|All: add eyecolor
• Humans|Pets|All: weight (kg)
• Humans|Pets|All: height (cm)
• Humans|Pets|All: age (years)
• Pets: add tail type (normal, bobtail, curled), defaults to normal in cats or curled in dogs, if not specified
• Pets: add fur length (short, medium, long, curled)
• Pets: add ears type (straight, curled, folded)
• Pets: breed (list of allowed breeds is up to you)
• Humans: add last name
• Humans: hair color (black, brown, blond, gray, red)
• Humans: hair type (straight, wavy, curly, kinky)
• Humans: hair length (long, medium, short, bald)

[OleksiyRudenko]

• Humans: Add method that changes first and last name (allow to specify only first or only last name). Test it on one of humans.