Add "extra info" field to menu system.
completed by: Aviral Dasgupta
mentors: David Bruce
For this task, modify TuxMath's menu system so that additional descriptive text can be displayed for the menu item that currently has focus.
It will be necessary to modify both menu.c in tuxmath, and t4k_menu.c in the t4k_common library.
Make sure all strings are marked for translation by GNU gettext.
When the task is done, supply separate patches for t4k_common and for tuxmath.