Release v0.7.1

Refactor assemble abundances

Having attempted to run the previous version of the pipeline on much larger datasets, it's clear that assembling a single table with all gene-level abundances is not computationally tractable.

The only impact of these changes on the output of the pipeline is that the /abund/gene/wide table is no longer present (neither is the matching feather file). In practice, the execution of the rest of the pipeline is unchanged.