0.2a

/**
* Title:    c-ray-f optimized with CUDA and Pthread
* Author:   Chi-chung Chen, Chi Chen
* Version:   0.2a
* Last modified: 2014/5/29
* Description:  1. Naively split "render" into 8 threads
*     2. Reduce huge overhead due to call by value
*     3. Reduce the number of multiplication when counting a, b, c, d in
"ray_sphere".
*     4. Incomplete x87 assembly
*
* Issue:   1. "ray_sphere" is the hottest function
*     2. Write inline assembly to speed up counting a, b, c, d.
*/