Commit 869de6d8 changed the signatures of definitions of various mp_*
functions but did not update the declarations in mp.h to match.

- implements Miller-Rabin primality test
- implements Pollard's rho algorithm to find prime factors
- adds mp_new_from_integer function for convenience

For further information please visit:
https://www.mpfr.org/
http://www.multiprecision.org/mpc

 cppcheck --enable=unusedFunction .
 [src/mp-binary.c:165]: (style) The function 'mp_mask' is never used.