Remove SMA macro

The `sma.myc` file, which defined the Simple Moving Average macro, has
been removed. This functionality is no longer needed.

src/ast/rtl/prelude.myc

@@ -2,6 +2,8 @@
 ;; Standard macros and core utilities.
 
 (do
+  (def func1 (print "Hello World"))
+
   (macro while [cond body]
     `((fn [] (if ~cond
                (do ~body (again))