Figure edits

[jjc2718]

Closes #50.

This PR makes some small changes to the figures and how they're generated, both from a previous PR (see linked issue) and from some collaborator feedback (see greenelab/mpmp-manuscript#24).

The major changes to the code are:

• Updating the multi-omics plot script to generate results for raw and compressed features (see 05_classify_mutations_multimodal/nbconverted/plot_multimodal_results.py)
• Updating the heatmap script to plot all statistically equivalent predictors as the "best" predictor, rather than just the one with the highest mean performance (see changes to mpmp/utilities/plot_utilities.py)

Additional changes are mostly small tweaks to color schemes, etc.

[jjc2718]

I refactored the plot script 05_classify_mutations_multimodal/plot_multimodal_results.ipynb to plot the results with both the compressed features (main paper) and raw features (supplementary figures), so they should both happen anytime the script runs. Let me know if this seems cleaner.