Bug Fix, Tweaks

- .taskrc debug= now defaults to 'off', which will reduce clutter
  and won't surprise beta testers.
- interactive.cpp did not compile when ncurses was not detected by
  autoconf.  That code branch obviously never got executed.
- The interactive shell now instructs the user to type 'quit' to
  leave the shell.

src/command.cpp

@@ -968,8 +968,8 @@ void handleShell ()
 {
   // Display some kind of welcome message.
   std::cout << ((context.config.get ("color", true) || context.config.get (std::string ("_forcecolor"), false))
-                 ? Text::colorize (Text::bold, Text::nocolor, PACKAGE)
-                 : PACKAGE)
+                 ? Text::colorize (Text::bold, Text::nocolor, PACKAGE_STRING)
+                 : PACKAGE_STRING)
             << " shell"
             << std::endl
             << std::endl
@@ -977,6 +977,8 @@ void handleShell ()
             << std::endl
             << "There is no need to include the 'task' command itself."
             << std::endl
+            << "Enter 'quit' to end the session."
+            << std::endl
             << std::endl;
 
   // Preserve any special override arguments, and reapply them for each