Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

Spell check

The default `SIGPIPE` handler installed by `TUnixSystem` does not do
anything except print a message and possibly causing an endless loop of
`SIGPIPE` handling:

```
echo 'std::cout << "foo" << std::endl;' | root -l |& true
python -c 'import ROOT; print "foo"' |& true
```

This fixes ROOT-4568 and ROOT-7659.

This will fix the issue that cling will try to invoke "OFF " to find headers.

Signed-off-by: Vassil Vassilev <vvasilev@cern.ch>

This commit removes the need of locking a weak pointer during the event loop,
taking advantage of the fact that we are guaranteed by TDataFrame's logic that
during the event loop TDataFrameImpl must remain in scope.

TDataFrame{Branch,Filter,Action} now store a raw pointer to the TDFImpl object.
TDataFrameInterface stores the weak_ptr<TDFImpl> in their stead.
As it was before, TDataFrameInterface is responsible for checking that the
TDataFrameImpl is still in scope before booking transformations and actions.

TDataFrameActionBase was the only TDataFrame.*Base object that did not
manage fTmpBranches and fFirstData.

Enables the possibillity to ignore tests that are longer than one minute
in order to reduce the overall build time.

They are not used in our environment but trigger a warning which breaks roottest.

This avoids generating warnings which in turn cause roottest failures.

Make SetLimits available from the TAxis GUI context menu as requested here: https://sft.its.cern.ch/jira/browse/ROOT-8707

when removing old paths make sure that $path:, :$path and $path are only matched
at the beginning, at the end, or match the whole string.

Refactor Interpreter::loadFile to call into these methods.