Added protection for ROOT-5428
Fix: https://sft.its.cern.ch/jira/browse/ROOT-4999
fix https://sft.its.cern.ch/jira/browse/ROOT-5431
In TMultiGraph::Add(TMultiGraph *multigraph, Option_t *chopt)
If "chopt" is defined all the graphs in "multigraph" will be added with the "chopt" option.
If "chopt" is undefined each graph will be added with the option it had in "multigraph".
Fix off by one error in out-of-bound check.

Avoid reading pass the end of an array in TTreeFormula.
This fixes http://root.cern.ch/phpBB3/viewtopic.php?t=16969.
Remove duplicate fTotal++;

Remove duplicate fTotal++; which is already incremented in the base class (TGLVContainer)
Solving a bug reported on the ROOT forum (http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=16971&sid=25ac93dfe11c8ea903e260b159f49519)
Improve the spacing between lines. Due to the way the vertical text centring is done (bounding based) the
spacing between lines may appeared irregular in some cases..