Move old FastWriter stuff out of new Builder

include/json/writer.h

@@ -36,7 +36,7 @@ Usage:
   std::shared_ptr<StreamWriter> writer(
     builder.newStreamWriter(&std::cout));
   writer->write(value);
-  std::cout.flush();
+  std::cout << std::endl;  // add lf and flush
 \endcode
 */
 class JSON_API StreamWriter {
@@ -77,24 +77,6 @@ public:
         Default: "\t"
     */
     Builder& withIndentation(std::string indentation);
-    /** \brief Drop the "null" string from the writer's output for nullValues.
-    * Strictly speaking, this is not valid JSON. But when the output is being
-    * fed to a browser's Javascript, it makes for smaller output and the
-    * browser can handle the output just fine.
-    */
-    Builder& withDropNullPlaceholders(bool v);
-    /** \brief Do not add \n at end of document.
-     * Normally, we add an extra newline, just because.
-     */
-    Builder& withOmitEndingLineFeed(bool v);
-    /** \brief Add a space after ':'.
-     * If indentation is non-empty, we surround colon with whitespace,
-     * e.g. " : "
-     * This will add back the trailing space when there is no indentation.
-     * This seems dubious when the entire document is on a single line,
-     * but we leave this here to repduce the behavior of the old `FastWriter`.
-     */
-    Builder& withEnableYAMLCompatibility(bool v);
 
     /// Do not take ownership of sout, but maintain a reference.
     StreamWriter* newStreamWriter(std::ostream* sout) const;