Advertise die type, update IAmADie message

[obasille]

In particular, we currently can't differentiate between a D6 and a D6 fudge

enum DieType
{
    DieType_D20,
    DieType_D12,
    DieType_D10,
    DieType_D8,
    DieType_D6,
    DieType_D6Pipped,
    DieType_D6Fudge,
    DieType_D4,
};