With this commit, we can now change option values in interactive mode with the
folowing special keys
- CTRL-L left_margin
- CTRL-R right_margin
- CTRL-D delimiter_align
- CTRL-I indentation
- CTRL-U ignore_unmatched
- CTRL-G ignore_groups
('ignores' option has been renamed to 'ignore_groups', but backward-compatible)
- Preserve indentation when a line starts with a delimiter
- Useful for aligning multi-line method chains
- Renamed `margin_{left,right}` to `{left,right}_margin
- Makes it easier to type in (`l`, `r`)
- `margin_{left,right}` is still supported
- Margins can be specified as the number of spaces, or as an arbitrary string
