REF: IntervalArray comparisons
- [ ] closes #xxxx
- [ ] tests added / passed
- [ ] passes `black pandas`
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

@jorisvandenbossche this is unrelated to the backing-data.  In the next commit I'll change the implementation to use left/right so as to be agnostic between the new/old backing formats. ok i am fine with this. @jorisvandenbossche any comments. @jorisvandenbossche i think ive addressed your comments, can you double check when convenient Thanks for the ping, will take a look tomorrow!