General changes

All these classes provide the same API.
    1. OH does now support ROOT graphs.
    2. The interface for graph publishing is the same as for histograms.
    3. One can use the classes OHRootProvider and OHRootReceiver to publish and receive graphs in ROOT format.
    4. The supported ROOT graphs are: TGraph, TGraphErrors, TGraphAsymmErrors as graphs with 2 axes and TGraph2D, TGraph2DErrors as graphs with 3 axes.
    5. Support for publishing TGraphBentErrors can be added with few changes immediately after TDAQ uses a newer ROOT release (>v5-12-00)
    6. The OHRawProvider has two more publish functions for graphs with 2 and 3 axes including error descriptions.
    7. See the Doxygen documentation about the mentioned classes for more detailed information.
    8. See also the example applications oh_graph_provider, oh_root_receiver and oh_raw_provider in the examples directory of the OH release.
    1. OH Display can now display all the supported graphs.
    2. A feature for changing the ROOT Draw options has been added. When publishing one can give an annotation to the graph/histogram to set the draw options. The last parameter of the publish function in OHRootProvider or OHRawProvider takes a vector of std::string pairs. If you provide a pair with the value "DrawOption" in the first element and your ROOT Draw option string in the second element, OH display will use these options to draw the graph/histogram.
    3. An example for the use of the draw option is given in the example applications oh_root_provider and oh_graph_provider in the examples/root_provider directory of the OH release.
    4. The bug that one could not send a command for a special histogram or graph is fixed.