Renamed osg::ComputeDispatch to osg::DispatchCompute to make sure the nameing between GL and OSG is consistent i.e glDispatchCompute -> osg::DispatchCompute

Updated AUTHORS.txt, NEWS.txt and README.txt for CMakeLists.txt for 3.6.0 release

src/osg/DispatchCompute.cpp

@@ -0,0 +1,16 @@
+#include <osg/DispatchCompute>
+
+using namespace osg;
+
+DispatchCompute::DispatchCompute(const DispatchCompute&o,const osg::CopyOp& copyop):
+    Drawable(o,copyop),
+    _numGroupsX(o._numGroupsX),
+    _numGroupsY(o._numGroupsY),
+    _numGroupsZ(o._numGroupsZ)
+{
+}
+
+void DispatchCompute::drawImplementation(RenderInfo& renderInfo) const
+{
+    renderInfo.getState()->get<GLExtensions>()->glDispatchCompute(_numGroupsX, _numGroupsY, _numGroupsZ);
+}