Adds a macro FMPZ_VEC_SWAP similar to MPN_SWAP.
Adds a macro FMPZ_VEC_SWAP similar to MPN_SWAP.

dsroche/flint2,wbhart/flint2,wbhart/flint2,jpflori/flint2,jpflori/flint2,fredrik-johansson/flint2,dsroche/flint2,jpflori/flint2,dsroche/flint2,wbhart/flint2,jpflori/flint2,dsroche/flint2,fredrik-johansson/flint2,fredrik-johansson/flint2