Add set index in list, and update lib+examples+tests

examples/list.ang

@@ -1,6 +1,6 @@
 
 # Empty list
-println([])
+println([]any)
 
 # List with items
 println([3, 1, 4, 1, 5, 9, 2, 6, 5])
@@ -8,25 +8,25 @@ println([3, 1, 4, 1, 5, 9, 2, 6, 5])
 # List with items of different types
 println(["", "私はかっこいいです。", true, nil, nil, 1, 2])
 
-a := []
+a := []int
 
-a = a + [1]
-a = a + [2]
+a.push(1)
+a.push(2)
 
 println(a)
 
 
-list := []
+list := []int
 
 x := 0
 for n in 0..100 {
     x = x + 2*n + 1
 
-    list = list + [x]
+    list.push(x)
 }
 
 println(list)
-println(list.map(func(a) {
+println(list.map(fn(a: int) -> int {
     return a - 1
 }))
 println(list.length())