configs/boardctl.c: Add boardctl() commands to replace direct calls to nxterm_redraw() and nxterm_kbdin().

TODO

@@ -2485,11 +2485,6 @@ o Graphics Subsystem (graphics/)
 
                Within the OS, NxTK currently used only in graphics/nxterm.  With
                some effort, I think NxTerm could be moved to apps/ as well.
-
-               Currently, nxterm violates POSIX interface.  nxterm_redraw() and
-               nxterm_kbdin() are called from applications.  see apps/examples/nxterm
-               and apps/graphics/NxWidgets/nxwm./src/cnxterm.cxx.
-
   Status:      Open
   Priority:    Low
 o Build system