Fix Streamer when the UserInfo contained TRef-ed objects.

When TTree::fUserInfo contains (directly or indirectly) an
object that is referenced by a TRef and (one of) the TTree
being processed has the BranchRef enabled, the TObject
Streamer will incorrectly.

See also ROOT-5922.
Handle URL's like: http://host?opt=1. Fixes ROOT-5915.

Also add new method HasOption(const char *key) which returns true if the
specified key appears in the URL option lists. In the above URL
HasOption("opt") returns true.
Merge branch 'v5-34-00-patches' of https://root.cern.ch/git/root into v5-34-00-patches
remove commented out code.
comment out new code that depends on server side includes. Needs fixing.
fix http://root.cern.ch/phpBB3/viewtopic.php?f=3&t=17502
Protect in case of only 1 point. Fix ROOT-5397
Fix a bug (ROOT-5200) in computing the bin errors in TH2::Smooth
Apply fixes for ROOT-5058

Add SetBins method in TEfficiency
Add new methods CreateGraph and CreateHistogram which create the histograms used to paint the class. They can now be called without drawing it.
 o) move gROOTModule into PyROOT namespace
 o) add special "gNullPtrObject" as identifiable NULL (nullptr)
meant '||' instead of '&&' ...
Adding copy constructors to build models using python more robustly.
bugfixes. Fix HF for models without any nuisance parameters.
Bugfix copy constructor for non-counting models.
When checking consistency of histogram (e.g. in TH1::Add)  check only the relevant axis (e.g ignore y and z axis for 1D histos)/
this fix ROOT-5249
Add an error messages in the TH1 methods which makes sense only for 1D histogram, like TH1::GetBinCenter.
This fixes ROOT-5049
Update documentation of TH1::KolmogorovTest as suggested in ROOT-4888
Fix coverity reports 54033 & 54034
Fix coverity report 50810
New example