iterative ref: MASTER ISSUE: Implement expectation maximization iterative refinement

[geoffwoollard]

Master issue of

• interative ref: insert slice notebook #53
• iterative ref: insert_slice from one plane #52
• iterative ref: more tests for insert_slice #50
• iterative ref: write tests for iterative_refinement #42
• iterative ref: test uniform distribution of SO(3) #39
• iterative ref: learn white noise (sigma) iteratively  #37
• iterative ref: log expectation maximization loss  #35
• iterative ref: Compute bayes factors with/without ctf convolution #32
• iterative ref: Generalize to use two separate half maps #31
• iterative ref: zero pad to avoid ctf aliasing #30
• iterative ref: implement and benchmark methods to normalize half maps #25
• iterative ref: make use of torch and compSPI 3D FFT.  #24
• iterative ref: expand_1d_to_3d #20
• iterative ref: compute_fsc #19
• iterative ref: insert_slice #18
• iterative ref: add more tests to wiener filter to test its functionality and limiting cases. #17
• iterative ref: compute_bayesean_weights #16
• iterative ref: generate_slices #15
• iterative ref: generate_xy_plane #14
• iterative ref: grid SO(3) with healpy #13
• iterative ref: build_ctf #11
• iterative ref: PR-ready docstrings and design for iterative refinement #10
• iterative ref: resources for expectation maximization iterative refinement #6
• iterative ref: extend white noise to coloured noise #5
• iterative ref: branch and bound #3

Tasks live in project Implement expectation maximization iterative refinement, one github issue per task.