Bug in BoundedRange's Iterator implementation

[rsnively]

There's an off-by-one error in BoundedRanges with an excluded lower bound. The following test fails:

#[test]
fn test_excluded_lower_bound() {
    let r = BoundedRange::new(Bound::Excluded(3), Bound::Excluded(4));
    assert_eq!(r.collect::<Vec<_>>(), vec![]);
}

with the message:

thread 'bounded_range::test_excluded_lower_bound' panicked at 'assertion failed: `(left == right)`
  left: `[4]`,
 right: `[]`', src/bounded_range.rs:136:5

[rsnively]

Fixed in 0.1.1

Specializing Bound into LowerBound and UpperBound made BoundedRange's iterator implementation make sense again.