In some ccache setups we have the compiler soft link to ccache.

Eg. /usr/local/bin/g++ -> /usr/local/bin/ccache. If we resolve the link too
early we will take the wrong branch assuming the compiler was set as
CMAKE_CXX_COMPILER="ccache g++" and try to get the second token of the command.

Patch by Roman Zulak <machtyrtle@gmail.com>!

Patch tested and requested by Chris Green (ROOT-8379).

The warning was due to code in place to prevent inconsistencies before
the full support of unique_ptr.

Added the option QUIET to find_python_module() function.

This fixes Github issue 113, breaking Jupiter notebooks.

Fix in `find_python_module` cmake function `REQUIRED` flag; adapt function so that it prints cause of error

Make `find_python_module` cmake function usable in py2 and py3; enable conditional testing of PyKeras

The new functions are:
   static Int_t GetGlobalDayFromDate(Int_t date);
   static Int_t GetDateFromGlobalDay(Int_t day);
   static Int_t GetLegalGlobalDayFromDate(Int_t date);
These functions are convenient when a series of dates is required.

See https://root.cern.ch/phpBB3/viewtopic.php?f=21&t=22515