Adding explicitely the impicit fortran libraries. This fixes the problem observed on MacOS with latest versions of gfortran.

* Add support for event weights in ROC calculations

* Update authors for ROCCurve

* Make TMVA factory use event weights

* Update authors of TMVA Factory

* Fix error in implementation of ROCCalc::ComputeSensitivity.

Also fixes axis labels and drawing direction to plot specificity on
x-axis and sensitivity on y-axis as is one standard.

* Fix ROC curve oscilation bug

Due to interpolation setting the ROC curve could sometimes be
non-monotonically decreasing. Changed to linear interpolation.

* Add ROC constructor for separate signal and background vectors

* Remove caching from ROCCurve::GetROCCurve

This since we might want to recalculate it with different
number of divisions.

* Fix ROC Curve crash when num_points < 2

* Format for clang-format

* Changes as discussed with L. Moneta

- Avoid unnecessary array copy
- Use reserve() to preallocate size of event arrays
- Use [] indexing instead of .at() since we assert sizes
- Use Double_t instead of Float_t for integral calc
- Flip axes of ROC plot

* Add documentation for ROCCurve public methods

* Fixes for clang-format

* More clang-format

* Last time with the doc clang-format

This issue was reported here: https://sft.its.cern.ch/jira/browse/ROOT-8751
It is now fixed.

The `TGraph` copy constructor also copy the underlying `TH1F` if it exists (it holds the axis titles).

As pointed out by Philippe: if requested by the user, a special branch (recorded in
TTree::fBranchRef) is created that keeps track of which branch contains objects that
are 'referenced' by TRef. Upon reading and then dereferencing of a TRef object,
TRef::GetObject is called which turns around and calls TBranchRef::Notify which will
call GetEntry on the branch.

There might be a race condition in the multi-threaded TTree::GetEntry if TRef::GetObject
is called during its execution. This is possible if the user inserts schema-evolution
rules that use the TRef. So it might be wise to pre-emptively load the TBranchRef in the
sequential section.

This avoids the deletion of the intermediate files.

Appends the same unique identifier to the name of the partial files
within the same hadd execution.

  by `TTree::Draw`. Three new parameter dre available in `$ROOTSYS/etcsystem.rootrc`

   Hist.Precision.1D:           float
   Hist.Precision.2D:           float
   Hist.Precision.3D:           float

  the fault values are `float`. They can be set to `double`.

the Snapshot method has been added to the TDF interface. This allows
users to write to disk in root format the dataset they read and modified
with the TDataFrame.
This works in single threaded mode only for now.

this has no effect on the interfaces but allows to cleanly return a new
TDataFrame from the TDataFrameInterface.

- Improve diagnostic output of compare() function
- Test inverted matrix times original against identity using
  element by element comparison, and use less strict tolerance
  to account for innacuracies due to matrix inversion

In some circumstances it might be NULL there.

In the input file of the aforementioned tutorial, some top-level branches
depended on another branch that determined their size for every entry
(e.g. the size of an array branch). When processing this kind of data,
branches that depend on size (or count) branches will trigger a call
to TBranch::GetEntry on the latter to ensure their size is read.

The scenario described above made the parallelization of TTree::GetEntry
thread-unsafe, since a count branch could be processed at the same time
by two tasks: its own task and the task that was processing the branch
that needed the size.

This has been solved by factoring out the count branches, which are
processed first sequentially and independently of the rest of the branches.
The latter can be processed safely in parallel afterwards because all the
sizes have been read already.