Add multiline echo macro example

multiline_echo.nim

@@ -0,0 +1,13 @@
+import macros
+
+macro echoAll(body: untyped): untyped =
+  result = newStmtList()
+  
+  for s in body:
+    result.add newCall(bindSym"echo", s)
+    
+    
+echoAll:
+  "Hello"
+  "World"
+  1234