Plot a clustered heatmap. The clustering is done by the hclust function.
plot_transcript_heatmap(obj, transcripts, units = "tpm", trans = "log",
offset = 1)a sleuth object
a vector of strings containing a list of transcripts to be plotted in a heatmap
a string specifying which units to use, either tpm or est_counts (scaled_reads_per_base for gene_mode)
a string specifying a function to transform the data by
a ggplot object