Add array example, ArrayObj implementation

* VM creates arrays using the BeginArray and EndArray instructions
* ArrayObj is implemented with a __str__ function (annoying)
* Simple example of array creation is added

Signed-off-by: Alek Ratzloff <alekratz@gmail.com>

examples/array.sy

@@ -0,0 +1,15 @@
+# Create an array with just some numbers
+{ 1 2 3 }
+println!
+
+[ :x x x ] :dup
+# Call some functions
+{ 1 dup! dup! }
+println!
+
+# Call your own functions, why not?
+{
+    [ 2 *! ] :double
+    1 dup! double! dup! double!
+}
+println!