Add a protection to fix the problem described here: https://sft.its.cern.ch/jira/browse/ROOT-5429
doc update
Blank space.
Hide InterpreterExternalSemaSource class as an implementation detail.
Remove private ctor.
Hide the callback adaptor classes in the implementation.
Subscribe to the interesting events.
For now we will only work/check on declarations that are not deserialized.

We don't want our null deref checker to deserialize the whole PCH/PCM. We should
come up with an idea to work around it.
Fix typo.
Move the PPCallbacks in InterpreterCallbacks too.
Use better method name. Improve documentation.
Fix init order warning.
Commit forgotten file. Documentation improvements.
Fix: https://sft.its.cern.ch/jira/browse/ROOT-4999
Merge branch 'master' of https://root.cern.ch/git/root
Reformatting according to the coding conventions.
fix https://sft.its.cern.ch/jira/browse/ROOT-5431
In TMultiGraph::Add(TMultiGraph *multigraph, Option_t *chopt)
If "chopt" is defined all the graphs in "multigraph" will be added with the "chopt" option.
If "chopt" is undefined each graph will be added with the option it had in "multigraph".
TMultiGraph
Fix off by one error in out-of-bound check.

Avoid reading pass the end of an array in TTreeFormula.
This fixes http://root.cern.ch/phpBB3/viewtopic.php?t=16969.

(cherry picked from v5-34-00-patch
 commit af5eeb4bdd7ecc59fa8cbb1c6927425a86017a71)