Renaming the system to 'DragonFly'

[Matthew Dillon]

    I've decided to move forward with renaming the system from FreeBSD
    to DragonFly.

    I am going to this incrementally.  My first commit will rename the
    system to DragonFly and will make sure that LINT and buildworld works
    when built on a FreeBSD-stable or a DragonFly system.

    These changes are almost guarenteed to break the ports system so for
    the next few days people should be aware that ports are going to be
    broken.

						-Matt