Switch nbsmoke to nbval
Switch nbsmoke to nbval

- `--nbval-lax`, which runs notebooks and checks for errors, but only compares the outputs of cells which include a `#NBVAL_CHECK_OUTPUT` marker comment.
- By default, each .ipynb file will be executed using the kernel specified in its metadata, a behaviour overridden by passing either `--current-env` to use a kernel in the same environment in which pytest itself was launched.
- Specify `-p no:python` if you would like to execute notebooks only. 
- ignore instrumentcontrol notebooks
temmeand/scikit-rf,scikit-rf/scikit-rf,temmeand/scikit-rf,jhillairet/scikit-rf,scikit-rf/scikit-rf,jhillairet/scikit-rf,jhillairet/scikit-rf,temmeand/scikit-rf