Module impls

Various region implementations.

Modules

• codec
  A region that encodes its contents.
• columns
  A region to contain a variable number of columns.
• deduplicate
  Simple deduplication of equal consecutive items.
• huffman_container
  A slice container that Huffman encodes its contents.
• mirror
  A region that copies its inputs.
• offsets
  Types to represent offsets.
• option
  A region that stores options.
• result
  A region that stores results.
• slice
  A region that stores slices.
• slice_copy
  A region that stores slices of copy types.
• string
  A region that stores strings.
• tuple
  Regions that stores tuples.