Document *FromArray variety of lifting methods
Replicate method lifting specs for *FromArray variety

Copy the specs for -rac_liftSelector:withObjects: and
-rac_liftBlock:withArguments: and adjust to test the *FromArray alternatives:
-rac_liftSelector:withObjectsFromArray: and
-rac_liftBlock:withArgumentsFromArray: respectively.
Add method lifting tests around handling nil