Added the LDClientAlias function. This can be used to associate two user objects for analytics purposes with an alias event.
Added the LDConfigAutoAliasOptOut function. This can be used to control the new behavior of LDClientIdentify. By passing true LDClientIdentify will not automatically generate alias events.
The LDClientIdentify method will now automatically generate an alias event when switching from an anonymous to a known user. This event associates the two users for analytics purposes as they most likely represent a single person.