add primesieve library

From http://primesieve.org/ website:
```
primesieve is a free (BSD-licensed) software program and C/C++ library that generates primes 
using a highlyoptimized sieve of Eratosthenes implementation. It generates the primes below 
10^9 in just 0.2 seconds on a single core of an Intel Core i7-4770 3.4GHz CPU from 2013. 
primesieve can generate primes and prime k-tuplets up to 2^64.
```