solving issue #112 on PlanesDeltaAngle functor

Merge pull request #115 from MultithreadCorner/develop-hydra4

Syncing master with develop-hydra4

Update README.md

Update Hydra.h

fixing polynomial coefficient in examples...

Update Hydra.h

Merge branch 'master' of https://github.com/MultithreadCorner/Hydra

 merging with master...

Update Hydra.h

 merging with master...