Fix bug in CalculusOperator and import DomainSets.domain

[dlfivefifty]

No description provided.

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 55.61%. Comparing base (023b1a4) to head (ab7d51d).
Report is 18 commits behind head on master.

Files with missing lines	Patch %	Lines
src/Operators/banded/CalculusOperator.jl	0.00%	1 Missing ⚠️

❗ There is a different number of reports uploaded between BASE (023b1a4) and HEAD (ab7d51d). Click for more details.

HEAD has 8 uploads less than BASE

Flag	BASE (023b1a4)	HEAD (ab7d51d)
	10	2

Additional details and impacted files

@@             Coverage Diff             @@
##           master     #664       +/-   ##
===========================================
- Coverage   75.20%   55.61%   -19.60%     
===========================================
  Files          79       81        +2     
  Lines        8445     8493       +48     
===========================================
- Hits         6351     4723     -1628     
- Misses       2094     3770     +1676     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[jishnub]

Could you add a test? The failure in ApproxFunOrthogonalPolynomials is unrelated, so we can go ahead