[Rd] unlist change the ordered type

[Christophe Genolini]

Hi the list,

unlist respect the all the atomic type except orderd (it change of 
ordered into factor) :

### integer
class(unlist(list(1:5,1:3)))
#[1] "integer"

### numeric
class(unlist(list(1.2,3.5)))
#[1] "numeric"

### character
class(unlist(list("e","e")))
#[1] "character"

### factor
class(unlist(list(factor("e"),factor("e"))))
#[1] "factor"

### ordered
class(unlist(list(ordered("e"),ordered("e"))))
#[1] "factor"

Christophe