moving specfun and image into extra/

updating list example
removing some examples that were basically copy&paste of other code

examples/list.jl

@@ -9,7 +9,7 @@ type Cons{T} <: List{T}
 end
 
 cons{T}(h::List{T}, t::List{List{T}}) = Cons{List{T}}(h, t)
-cons(x,y) = Cons(x,y)
+cons{T}(h, t::List{T}) = Cons{T}(h, t)
 
 nil(T) = Nil{T}()
 nil() = nil(Any)
@@ -43,7 +43,20 @@ end
 
 list() = nil()
 list{T}(first::T) = cons(first, nil(T))
-list(first, rest...) = cons(first, list(rest...))
+function list(elts...)
+    l = nil()
+    for i=length(elts):-1:1
+        l = cons(elts[i],l)
+    end
+    return l
+end
+function list{T}(elts::T...)
+    l = nil(T)
+    for i=length(elts):-1:1
+        l = cons(elts[i],l)
+    end
+    return l
+end
 
 length(l::Nil) = 0
 length(l::Cons) = 1 + length(tail(l))
@@ -64,7 +77,7 @@ end
 
 append(lst::List) = lst
 
-function append{T}(lst::List{T}, lsts...)
+function append(lst::List, lsts...)
     n = length(lsts)
     l = lsts[n]
     for i = (n-1):-1:1