This reverts commit f9e2adf8.
Use the "no fail" approach instead.

This requires a special treatment and a new use case

The power-of-2 autobinning algorithm makes sure that resulting histograms are automatically
mergeable using powers of 2 for boundaries, ranges and number of bins.
The first implementation defines the relevant methods and implements them for the
1D case.
In order to use this method the new bit TH1::kAutoBinPTwo must be set.
The method AutoP2FindLimits depends on the number of dimensions and needs to be
re-implemented for TH2 and TH3.

(cherry picked from commit a4235ec91bdf35b2356855cac3fa19710259e4fd)

(cherry picked from commit 2f552ae4ffc4b64a66aafd47f250ef2e3df31441)

[graf2d/asimage/src/libAfterImage/afterbase.c:1282]: (style) Array index 'i' is used before limits check
[graf2d/asimage/src/libAfterImage/libungif/gifalloc.c:61]: (error) Memory leak: Object
[graf2d/win32gdk/src/TGWin32.cxx:4540]: (error) Memory leak: GIFarr
[graf3d/eve/src/TEveCalo2DGL.cxx:169]: (error) Memory leak: sliceVal
[graf3d/eve/src/TEveCalo2DGL.cxx:169]: (error) Memory leak: sliceValRef
[graf3d/eve/src/TEveCalo2DGL.cxx:369]: (error) Memory leak: sliceValsUp
[graf3d/eve/src/TEveCalo2DGL.cxx:369]: (error) Memory leak: sliceValsLow
[graf3d/eve/src/TEveCalo2DGL.cxx:369]: (error) Memory leak: sliceValsUpRef
[graf3d/eve/src/TEveCalo2DGL.cxx:369]: (error) Memory leak: sliceValsLowRef
[graf3d/eve/src/TEvePointSet.cxx:354]: (error) Memory leak: subarr

[graf3d/gl/src/gl2ps.cxx:1382] -> [graf3d/gl/src/gl2ps.cxx:1382]: (style) Same expression on both sides of '|'
see http://octave.org/doxygen/3.6/d3/d9c/gl2ps_8c_source.html#1343

[hist/hist/src/TFormula.cxx:1741]: (style) Array index 'i' is used before limits check.
[hist/hist/src/TFormula.cxx:1810]: (style) Array index 'i' is used before limits check.
[hist/hist/src/TGraphSmooth.cxx:173]: (style) Array index 'imin' is used before limits check
[hist/hist/src/TPrincipal.cxx:714]: (error) Memory leak: hX
[hist/hist/src/TPrincipal.cxx:714]: (error) Memory leak: hD
[hist/hist/src/TPrincipal.cxx:714]: (error) Memory leak: hP

[hist/histpainter/src/TGraph2DPainter.cxx:416]: (style) Array index 'js' is used before limits check.
[hist/histpainter/src/TGraph2DPainter.cxx:455]: (style) Array index 'js' is used before limits check.
[interpreter/llvm/src/tools/bugpoint/ToolRunner.cpp:386]: (error) When Pos==CommandLine.size(), CommandLine[Pos] is out of bounds

+Prefer prefix ++/-- operators for non-primitive types

(cherry picked from commit 52dd84061dbcee5fa670b0cf42cec93f15e41819)

This assumption caused a breakage in datasource_csv.cxx and in the
same that caused breakages in datasource_root.cxx (fixed by
commit feab873b).

If we preload the core modules that can contain complex.h, we
break a lot of tests that name variables or template arguments I.

Without modules, many STL and libc headers are automatically
provided by ROOT via the attached ROOT PCH. This means that
we don't need to have autloading or explicit includes for STL
or libc headers when running with the PCH attached. This leads
to making user code like this working in ROOT:

```C++
// no includes here that provides assert
int foo() {
  assert(false);
}
```

However, as the modules don't come with this big PCH, we
are now suddenly in the situation where we can't resolve
things such as `assert`. We also can't rely on the
normal autoloading of ROOT as those declarations were
actually never autoloaded, but just provided by the PCH.

To simulate this behavior with modules, we automatically load
those headers that we expect to have in the ROOT PCH
(which are probably the STL and libc headers).

Thanks Axel!

Merge branch '0006-GlobalRWLock'

When allowing concurrent remove, the link's element might be nullptr before the end of the list

This allows THashList to also set the flag of its THashTable.

Also added:
  status bit kUseRWLock (which value is private)
  TCollection::IsUsingRWLock