Function: bitflip
C-Name: bitflip
Section: conversions
Prototype: vWL
Help: bitflip(~x,n): flip bit n of x in place, assuming x >= 2^(n+1).
Doc:
 Flip \emph{in place} the $n^{\text{th}}$ bit of the integer $x \geq 2^{n+1}$
 starting from the right, i.e.~the coefficient of $2^{n}$ in the binary
 expansion of $x$. See \kbd{bitset} for details.
 If you need to flip an higher bit, use \kbd{x = bitxor(x, 1<<n)}.
