Create rand_sfmt.c

A Fast single thread Gaussian ziggurat implementaton for  large 2-D, complex matrix, random numbers in .c   It is a derivation from sfmt.c and dsfmt.c and the gsl gausszig.c routines

This is the fastest version to date , and is 20% faster than the posix, pthread_create() version with two threads.  Developed in gcc 4.8.2