ENH Add `gname` attribute to Uniprot entries
RFCT Use XPath objects instead of Python

These get compiled once and then applied many times. I expect it to be
faster
BUG Use sqlite in asynchronous mode

Finally, a solution that works 100%

Previously, only the first session was actually correctly in
assynchronous mode. Now, indexing in unsafe mode takes >90% CPU, as it
should.