178 SbMatrixd and SbRotationd missing from Coin.

    These classes are present both in TGS Inventor and in Coin, but in
    Coin they are named SbDPMatrix and SbDPRotation. They should also
    be named the same in Coin, to make migration easier.

    Is it possible / sufficient to fix this with a simple typedef?

    20041210 mortene.
