Animate splicing gene transcripts

[eweitz]

This splices transcripts smoothly, letting users track where exons, introns and UTRs end up, and their relative size change.

By having a brief, gradual change rather than an instant change, users can often visually follow how the location and proportional length of individual transcript subparts evolve between spliced and unspliced states. This extends previous work in #313 and #318.

This genomic animation technique might be adapted for future gene-scoped features.

Here's how it looks:

Animated_gene_transcript_splice__Ideogram_2022-10-14.mp4

[coveralls]

Coverage increased (+0.2%) to 86.714% when pulling 2209144 on animate-splice into 6c0acb4 on master.