Input/readme removed gesturemanipulator reference
Input/readme removed gesturemanipulator reference

Address issue https://github.com/Microsoft/HoloToolkit-Unity/issues/431
willcong/HoloToolkit-Unity,NeerajW/HoloToolkit-Unity,dbastienMS/HoloToolkit-Unity,HoloFan/HoloToolkit-Unity,ForrestTrepte/HoloToolkit-Unity,out-of-pixel/HoloToolkit-Unity,davesmits/HoloToolkit-Unity,paseb/MixedRealityToolkit-Unity,HattMarris1/HoloToolkit-Unity,CameronVetter/HoloToolkit-Unity,paseb/HoloToolkit-Unity,chadbramwell/HoloToolkit-Unity,vbandi/HoloToolkit-Unity,darax/HoloToolkit-Unity