Timed Game for a school project.

Files:

// generic
    tools           -- generic tools
    alloc           -- wrappers to check return values of dynamic allocation functions
    list            -- manage singly-linked lists
    timer           -- alarm-based timer
    sigmsg          -- messages-based inter-processus communication

// program-dependant
    msgs            -- sigmsg wrappers
    game            -- low-level management of a game
    menu            -- menu management
    menu_functions  -- handlers of the different functions of the menu