Get Sequences by Taxon ignores entrez_retmax #14

Claude reports: "Get Sequences by Taxon" ignores the entrez_retmax setting. With "entrez_retmax": "2" in the user settings, taxon 10710 offers Download 163 sequences? and would fetch all of them (Entrez.efetch at line 237 is called without retmax). "Get Sequences by Search" honours the setting (Download 3 sequences? 'retmax': 2 and 2 records arrive).

A large taxon (for example 9606) would try to download an enormous number of GenBank records on Sublime's main thread.

Fix: pass the same retmax to the taxon command and show it in the dialog, or document that it is not limited.

Tested on Sublime Text build 4215 (portable, Windows), plugin host Python 3.14, installed through Package Control (BioPythonUtils 2017.12.18.15.00.45, which contains the fixes for #3). Line numbers are those of BioPythonUtils.py on master (de058c4).