This reimplements the history functions in readline.

- Use regular lists instead of homegrown list implementation
- Allocate history strings dynamically instead of copying strings
  to fixed buffers without checking the size
- saves us an initcall
- slightly smaller
- no longer add duplicates to the history
- when moving past the last history entry print an empty line

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>