make getNewLineCharacter errorproof

lib/ace/document.js

@@ -140,16 +140,16 @@ var Document = function(text) {
     * 
     **/
     this.getNewLineCharacter = function() {
-      switch (this.$newLineMode) {
+        switch (this.$newLineMode) {
           case "windows":
-              return "\r\n";
+            return "\r\n";
 
           case "unix":
-              return "\n";
+            return "\n";
 
-          case "auto":
-              return this.$autoNewLine;
-      }
+          default:
+            return this.$autoNewLine;
+        }
     };
 
     this.$autoNewLine = "\n";