* [TMVA] CV - Add workaround for large event numbers

Currently TMVA considers all internal variables floats, if large event
numbers are then input as part of "cv-in-app" these can overflow the
float resulting in erroneous fold assignments.

A workaround is to reduce the input range when reading the input from
the TTree as TTreeFormula retains awareness of the input type.

Throws IndexError if index is out of bounds and also makes it possible
to iterate over a TArray.

Throws IndexError if index is out of bounds and also makes it possible
to iterate over a TVector3.

Throws IndexError if index is out of bounds and also makes it possible
to iterate over a TVectorT.

Add possiblity to set collection in the table view. Fixes related to collection filtering and event loops.

As an aftermath of the fix for ROOT-9777, the class version of ModelConfig
needed to be incremented to silence a warning when reading old versions of
the class.

Fix a potential crash (at least on Windows) when a TBrowser is open and one quit ROOT with the Web Canvas' button

- in the ~RWebWindowsManager() dtor, call the correct Disconnect() method and add fServer->SetTerminate()
- in TQObject::Disconnect(), protect against potential null pointer

Use explicit constructors, reduce number of constructors for some
classes

Just for debugging, let stop ROOT and close browser window

Where it possible, otherwise use old iterator API