Removed misleading HOWTO.
Removed misleading HOWTO.

The Hipparchus project has not decided yet on its branching model.
Hipparchus-Math/hipparchus,Hipparchus-Math/hipparchus,sdinot/hipparchus,sdinot/hipparchus,Hipparchus-Math/hipparchus,Hipparchus-Math/hipparchus,sdinot/hipparchus,sdinot/hipparchus