+ added multithreading support;
+ fixed pointer to threads[i] and bumped version to 0.03;
* renamed cpus to threads to avoid confusion;
+ added some comments to explain code better;
+ switched to dynamic allocation of process structures;
* fixed segmentation fault, while initializing libgmp stuff;
+ added printing results as a default, for big digits value only last 50 are printed;
+ added -O2 as a default to Makefile;
* fixed missing new line;