Usage of initializer list in for loop to iterate over heavy types
has bad consequences. std::initialize_list is only a view and its
data is silently created as T[N]. Therefore, if someone uses
std::vector with it, it will cause deep-copying of the elements.
This change introduces usage of pointers on std::initializer_list
to perform a shallow-copy of an addresses. Furthermore, it adds
const references in few places, where copy is not needed.
Signed-off-by: Patryk Wrobel <patryk.wrobel@intel.com>