Replace glut timing with the timer utility class

This was causing unresolved external symbols when compiling in 64 bit,
probably because glut was built for 32 bits. Even though these changes
don't affect the 32-bit build, I added them to this branch so try to
keep the code differences between the two minimal.
Enable multicore compilation
Update OpenCV from 231 to 245

The reason I'm updating OpenCV is because I don't have the 64-bit
version of 231. 245 comes with both x86 and x64.
Replace libjpeg with libjpeg-turbo

This is because I couldn't find a 64-bit version of libjpeg, plus
libjpeg-turbo is supposedly faster, with the benefit of having the
exact same api.