Update all examples to match v3

[elisachisari]

We should verify that all examples work and if not, update them. This is the list of Jupyter networks that need to be revisited:

• [ ] examples/3x2demo.ipynb
• [ ] examples/Halo model.ipynb
• [ ] examples/Correlation.ipynb
• [ ] examples/RSD_benchmark.ipynb
• [ ] examples/Correlation_3d.ipynb
• [ ] examples/Correlation_3dRSD.ipynb
• [ ] examples/SLAC Feb2018 Demo.ipynb
• [ ] examples/GeneralizedTracers.ipynb
• [ ] examples/RSD_benchmark_read.ipynb
• [ ] examples/Benchmark_Comparisons.ipynb
• [ ] examples/NFW_profile_3D_2D_demo.ipynb
• [ ] examples/Power spectrum example.ipynb
• [ ] examples/MCMC Likelihood Analysis.ipynb
• [ ] examples/Halo-mass-function-example.ipynb
• [ ] examples/Distance Calculations Example.ipynb
• [ ] examples/muSigma_modified_gravity_demo.ipynb
• [ ] examples/Lensing angular power spectrum.ipynb
• [ ] examples/Reading-writing-Cosmology-objects.ipynb

[elisachisari]

Upon discussion on the Slack channel, we are probably going to get rid of some of these examples. I would propose to re-structure examples as follows:

• [x] An example for core functions like H(z), distances, etc. Anish
• [x] An example for power spectra functionality, including halo model and MG. Cristhian
• [x] An example for Cells + correlations. @empEvil
• [x] The benchmark comparison notebook. @elisachisari
• [x] examples/Reading-writing-Cosmology-objects.ipynb Anish
• [x] examples/NFW_profile_3D_2D_demo.ipynb - JiachuanXu
• [x] examples/MCMC Likelihood Analysis.ipynb @nesar
• [x] examples/GeneralizedTracers.ipynb @mishakb

We'd go from 18 notebooks to 8. We'd be losing the RSD and the 3D correlation, but they appear in the benchmark notebook. Thoughts?

[elisachisari]

So I'm thinking of keeping the benchmark notebook in this repo. This is where all the benchmark testing happens and otherwise we'd have to duplicate all the benchmark files in the CCLX repo. The other examples we would move.

[elisachisari]

I'm adding the HMF notebook to the list of ones to keep. It doesn't represent unreleased capabilities at the moment, but it runs with v2.

[c-d-leonard]

@elisachisari are we happy with this issue being resolved or do you want to wait till we merge the benchmark notebook pr?