Feature/add review pr option

use `./eb --review-pr 1017 -D | less -R` to try this out.
TODO:
 - [ ] Compare with other files found in the same PR
 - [ ] add legend on top
 - [ ] add documentation / docstrings
 - [ ] figure out how to display added/removed spaces



maybe use
```python
line_no_dict = self.diff_info.setdefault(line_no, {})
line_no_dict_key = line_no_dict.setdefault(key,[])
line_no_dict_key.append((diff_line.rstrip(), meta, squigly_line))
```