Enhancement - echo ID on add

- When a task is added, the new ID is echoed back, for convenience.
  This requires a scan of the pending file, so there is a performance
  hit, and the feature is controlled by the FEATURE_NEW_ID define.

src/rules.cpp

@@ -283,12 +283,12 @@ std::string colorizeFootnote (const std::string& input)
 ////////////////////////////////////////////////////////////////////////////////
 std::string colorizeDebug (const std::string& input)
 {
-  if (gsFg["debug.footnote"] != Text::nocolor ||
-      gsBg["debug.footnote"] != Text::nocolor)
+  if (gsFg["color.debug"] != Text::nocolor ||
+      gsBg["color.debug"] != Text::nocolor)
   {
     return Text::colorize (
-           gsFg["debug.footnote"],
-           gsBg["debug.footnote"],
+           gsFg["color.debug"],
+           gsBg["color.debug"],
            input);
   }