1. backend: introducing the new Task API
2. backend: Allow opening the file using memory mapping (mmap), by default off.
3. toolkit: Fixes Simulate growth
4. toolkit: Enable clipping of file in the initial evaluation in the toolkit.
5. toolkit: Fixes an error in the live option to plot using bokeh.
6. testing: add Python 3.9 support
7. gui: added animated eta logo
8. gui: Reload the cached GUI everytime, to avoid being stuck on older GUI versions in electron
This release coincides with the publication of our paper [Z. Lin et al (2021 JINST 16 T08016)](https://doi.org/10.1088/1748-0221/16/08/T08016) describing the ideas behind ETA.