Version 0.1.2

Small optimization/cleanup release here.

- Fixed `StackBlur` behavior with repeating iterators. It used to
  just continue without returning a `None`. Now it properly returns a
  `None` before continuing.

- Switched to new `imgref-iter` iterators. These are relatively immature
  (I made them in about 4 hours) but they simplify the implementation of
  `blur_horiz`, `blur_vert` and `blur` massively, as well as possibly
  benefitting the ecosystem of crates that use `imgref`, since anyone
  can use the crate.

- `blur` has been optimized slightly to avoid allocating more than one
  deque. It used to allocate two because it called `blur_horiz` and
  `blur_vert` individually.

The perf increase is barely anything. Larger increases are planned from
things like `rayon` and SIMD.

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = 'stackblur-iter'
-version = '0.1.1'
+version = '0.1.2'
 authors = ['LoganDark']
 edition = '2021'
 rust-version = '1.56'