Fix bugs in tuneup.
Merge branch 'master' of https://github.com/wbhart/mpir
Apparently I didn't update these correctly.
Update to latest mpz_gcd and mpz_gcdext from GMP.
Merge branch 'master' of https://github.com/wbhart/mpir
Update to GMP 5.1.3 factorial code.
Merge branch 'master' of https://github.com/wbhart/mpir
Update Windows Visual Studio 2013 build for latest changes