Before, makepchinput.py was not removing some files because they were misnamed (allLinkDef.h vs allLinkDefs.h, cppflags.txt vs allCppflags.txt).
Now, let the caller send consistent file names for "remove old files".
Remove duplicate allDict.cxx.h (sic!) removal.
Also remove allDict.cxx.pch which seems to exist, sometimes?

Often, when designing an analysis, it happens to deal with empty RVec instances,
for example after a selection cut. This change allows in an ergonomic way to
deal with this case without imposing overhead on the user.

* Fix bad formulas/typos in docs, clarify SplitRange() feature of RooAbsPdf.

* Typos, misplaced comments, clarifications.

This was not causing the observed failures.

This reverts commit ede6463b.

in order to make the interactive experience in python and at the
prompt more rewarding:
```
root [0] ROOT::Math::XYZTVector v
(ROOT::Math::XYZTVector &) (0,0,0,0)
```

this commit suggests to prefer the usage of ROOT::Math::TLorentzVector
specialisations instead of the TLorentzVector class given the
advantages of the former.
- Release notes are changes
- The documentation of TLorentzVector updated to point to the specialisations of ROOT::Math::TLorentzVector
- The RDF tutorials using TLorentzVector upgraded

This reverts commit 2b071027.

Try to appease the incremental builds. They fail with:

In file included from test_Persistency1_C_ACLiC_dict dictionary payload:7:
./test_Persistency1.C:69:8: error: redefinition of 'Event'
struct Event : public DataObject  {
       ^
/.../roottest/root/tree/cache/Event.h:103:7: note: previous definition is here
class Event : public TObject {
      ^
In file included from test_Persistency1_C_ACLiC_dict dictionary payload:7:
./test_Persistency1.C:86:8: error: no member named 'm_evt' in 'Event'
    d->m_evt = d->m_run = i;

to get better performance.

This fixes ROOT-10057

/build/jenkins/night/LABEL/mac1014/SPEC/cxxmod-noimt/root/test/testGenVectorVc.cxx:194:1: error: redefinition of 'Point' as different kind of symbol
using Point = ROOT::Math::PositionVector3D<ROOT::Math::Cartesian3D<T>, ROOT::Math::DefaultCoordinateSystemTag>;
^
In module 'Darwin' imported from /Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/assert.h:42:
/Library/Developer/CommandLineTools/SDKs/MacOSX10.14.sdk/usr/include/MacTypes.h:538:8: note: previous definition is here
struct Point {
^

See  http://root-forum.cern.ch/t/tselector-ttreereader-and-fchain-setentry/30170/1
and http://root-forum.cern.ch/t/problem-with-multiple-files-in-tchain-with-makeselector-class/32534/7

Without this patch for Name<Content>::Inner, MakeProject was using Name<Content,::Inner>::Inner.

in order to make of this code the most up-to-date set of examples possible.

GetEntry is not thread-safe anyway, and GetEntriesUnsafe is faster.

GetEntriesFast is not as fast as it could be: it constructs and
destructs a TReadLockGuard, and might need to modify fLast.
GetEntriesUnsafe is a thread-unsafe version of GetEntriesFast
that side-steps these operations when possible.

The operation is relatively costly as TObjArray::GetEntries also
creates a TReadLockGuard.

From V.Vasilev, it fixes:
[ 72%] Building CXX object interpreter/llvm/src/tools/clang/lib/CodeGen/CMakeFiles/clangCodeGen.dir/CodeGenModule.cpp.o
While building module 'Cling_Interpreter' imported from /.../root/core/clingutils/src/RStl.cxx:25:
In file included from <module-includes>:5:
 /.../root/interpreter/cling/include/cling/Interpreter/RuntimeUniverse.h:13:2: error: "This file must not be included by compiled programs."
 #error "This file must not be included by compiled programs."
 ^