Trinucleotide context heatmaps for multiple sample comparisons

[clintval]

Plot count or density heatmaps for a list of spectra with k=3 and identical reference_notation.

Figure 1A: Differences in mutation burden and spectra between carcinogen and genetic models¹

1 Westcott et al. (2014) The mutational landscapes of genetic and chemical models of Kras-driven lung cancer

[clintval]

For plots like this, we will need to implement a SpectrumCollection class validating that all spectrums are of equivalent types. SpectrumCollections will also provide methods for grouping, sorting and will be used as input to clustering/decomposition routines.