Remove IndexOutOfBoundsError

src/common/errors.rs

-#[derive(Fail, Debug)]
-#[fail(display = "Supplied an invalid index")]
-pub struct IndexOutOfBoundsError;
-
 #[derive(Fail, Debug, PartialEq)]
 #[fail(display = "The supplied bitvector is not valid for this tree.")]
 pub struct InvalidBitvecError;