Handle cursor key mode (application vs. ANSI). "less" now works.

terminal.hpp

@@ -43,6 +43,9 @@ namespace Terminal {
     std::string read_octets_to_host( void );
 
     void debug_printout( int fd );
+
+    std::string open( void ); /* put user cursor keys in application mode */
+    std::string close( void ); /* restore user cursor keys */
   };
 }