cleanup of fmpz_t and fmpz_poly_t to avoid Cython warnings about referencing before assignment
silence Cython warning about complicated declaration
merge
Merge with 6.4.beta1

Conflicts:
	src/sage/libs/flint/fmpz_poly.pxd
trac #16583, oops, correcting wrong merge
Remove stuff which is not needed
Further cleanup
Trac #16583: Clean up FLINT declarations

Update fmpz.pxi and fmpz_poly.pxi (and others) so that Cython doesn't
complain about referenced before assigment any more.

URL: http://trac.sagemath.org/16583
Reported by: malb
Ticket author(s): Martin Albrecht
Reviewer(s): Jeroen Demeyer