- Finalized the interface by :

        * Having an epoll_event structure instead of using the pollfd
        * Adding a 64 bit opaque data member to the epoll_event structure
        * Removing the "fd" member from the epoll_event structure
        * Removing the "revents" member to leave space for a unique 32 bit
                "events" member

- Fixes the problem where, due the new callback'd wake_up() mechanism
        loops might be generated by bringing deadlock or stack blow ups.
        In fact a user could create a cycle by adding epoll fds inside
        other epoll fds. The patch solves the problem by either :

        * Moving the wake_up() call done on the poll wait queue head,
                outside the locked region
        * Implementing a new safe wake up function for the poll wait queue
                head

- Some variable renaming

- Changed __NR_sys_epoll_* to __NR_epoll_* ( Hanna Linder )

- Blocked the add operation of an epoll file descriptor inside itself

- Comments added/fixed