- fixed lag window off-by-1 indexing bug
  - the window was started 1 sample early but the timing of the
    windowed data was okay so this is only a minor issue
- symmetric_correlations is far faster now
- noise_stack uses symmetric_correlations and fixes a related bug
- coverage function now works
- plot0 updated to handle dataless records better
- noise_c3 fixed to properly reset verbosity