missing Java binding for mpfr_number_p

[yilongli]

int mpfr_number_p (mpfr_t op) checks if op is an ordinary number. http://www.mpfr.org/mpfr-current/mpfr.html#MPFR-Interface

[dwightguth]

Even with Omer's patch for this issue, we are likely not going to update the binary in the maven repo immediately because we haven't completely solved the issue of multiplatform release yet. However, I should point out that an acceptable workaround can be derived from the fact that a floating point is an ordinary number if it is not a NaN and not an infinity, both of which are currently checkable individually.