Demonstrate how to get the size of a variable.

See also: Host introspection

(123).len() //-->1 (byte)
(0).MAX.len()   //-->8 (bytes), ie the max number of bytes in an int
(1.0).MAX.len() //-->8 (bytes), ie the max number of bytes in an float
"this is a test".len() //-->14
L(1,2,3,4).len()   //-->4
Dictionary("1",1, "2",2).len() //-->2 (keys)
Data(0,Int,1,2,3,4).len() //-->4 (bytes)
Data(0,String,"1","2","3","4").len() //-->8 bytes (ASCIIZ)