Babel: add results value support to Scala

* lisp/ob-scala.el (org-babel-scala-wrapper-method): Use a Scala
block enclosing the submitted code.

The string representing an well formed block was not an Scala code. I
put the string from the user into an block, surrounded by an call to
replace the default output stream.

TINYCHANGE

lisp/ob-scala.el

@@ -72,9 +72,17 @@ Emacs-lisp table, otherwise return the results as a string."
 
 
 (defvar org-babel-scala-wrapper-method
-  "(
+
+"var str_result :String = null;
+
+Console.withOut(new java.io.OutputStream() {def write(b: Int){
+}}) {
+  str_result = {
 %s
-) asString print
+  }.toString
+}
+
+print(str_result)
 ")