Revert "re-enable tests of Vc"

This reverts commit 45ea7c2a54cbca3c7987ae497b0d5ce0ca425abc.
add again modifications to re-nable Vc tests
Revert "Rename ROOT::Shadow to ROOTShadow::Shadow against MSVC 12,13 bug."

This reverts commit 6ffe54a00a112ba551a63e098cb44ffeb67b5c63.

It doesn't work around the MSVC compiler bug...
Add special compiler flags for Vc for clang (copy what is done from vc/cmake/VcMacros.cmake)
Add missing #include <algorithm> (std::min and std::max are defined in algorithm)
Add missing #include <algorithm> (std::min and std::max are defined in algorithm)
Add missing #include <algorithm> (std::min and std::max are defined in algorithm)
Add missing #include <algorithm> (std::min and std::max are defined in algorithm)
Add missing #include <algorithm> (std::min and std::max are defined in algorithm)
correctly locate JavaScript ROOT sources, using ROOTETCDIR define

Signed-off-by: Bertrand Bellenot <bertrand.bellenot@cern.ch>
Fixes for ubuntu. Add linking of libgsl and libgslcblas before ROOT libraries (e.g. libMathore)