- Added settings.
- Fixed delete backward path.
- Added prompt example.
Merge pull request #190 from zhaocai/pull_request/bookmark_star

- Improve bookmark source, `*` argument to load from all
- Improved unite status line.
- Improved message behavior.
- Refactored a bit.
- Improved for preview window.
- Fixed no_quit behavior.
- Added <Plug>(unite_print_message_log) mapping.
- Improved message color.