Update the Human Pet

This Pet Type has currently not been added to the game, as I have not
yet discovered a way to successfully send the reuquired information to
the clients about skins. Even the Steve skin doesn't work yet. It
throws errors, as the "Monster" entity (ID 49) no longer has a texture
client-side.
All Pets are now able to fly
Pets now respawn with the player
Add default constructors to all Pets
Increase Dragon flying speed