Feature #934

- Feature #934, supports 'reserved.lines' to indicate a multi-line prompt for
  use in conjunction with 'limit:page' (thanks to Robert Gill).
- Removed 'locale' from the taskrc.5 man page.
- Added verbosity token 'sync'.
- Fixed bug in size calculation for 'limit:page', but there is still one more.
- Corrected unit test limit.t given the above fix.

src/main.h

@@ -76,6 +76,7 @@ void feedback_affected (const std::string&, int);
 void feedback_affected (const std::string&, const Task&);
 void feedback_special_tags (const Task&, const std::string&);
 void feedback_unblocked (const Task&);
+void feedback_backlog ();
 std::string onProjectChange (Task&, bool scope = true);
 std::string onProjectChange (Task&, Task&);
 std::string onExpiration (Task&);