Chapter 10.3 : Let's swap the loops over j and k

• 10.3.1) The sgemm_swap.h file
• 10.3.2) The sgemm_swap.cpp file
• 10.3.3) The main_sgemm_swap.cpp file
• 10.3.4) The CMakeLists.txt file
• 10.3.5) The compilation
• 10.3.6) The performances

Let's change the kernel by swaping loops over j and k.