Merge branch 'improve_sphere' into 'master'

Improve implementation of `SplineSurface`

See merge request uhlmann-group/python-spline-fitting-toolbox!5
1 job for master in 17 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Test
failed #412126
tests

00:00:17

 
Name Stage Failure
failed
tests Test There has been a runner system failure, please try again
Using Docker executor with image continuumio/miniconda3:latest ...
Pulling docker image continuumio/miniconda3:latest ...
ERROR: Preparation failed: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit (docker.go:142:1s)
Will be retried in 3s ...
Using Docker executor with image continuumio/miniconda3:latest ...
Pulling docker image continuumio/miniconda3:latest ...
ERROR: Preparation failed: toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit (docker.go:142:1s)
Will be retried in 3s ...
ERROR: Job failed (system failure): toomanyrequests: You have reached your pull rate limit. You may increase the limit by authenticating and upgrading: https://www.docker.com/increase-rate-limit (docker.go:142:1s)