upgrade to sequenceserver 2.0.0

[loraine-gueguen]

https://github.com/wurmlab/sequenceserver/releases/tag/2.0.0

of particular interest:

• We have introduced an optional, experimental widget to display databases in tree format - very helpful if you have a long list of databases. The feature was contributed by @Bjoernsen (Idea: database structure/tree wurmlab/sequenceserver#520) and is similar to what was previously produced by lepbase (Improved Display of a Long List of Database wurmlab/sequenceserver#307). See Idea: database structure/tree wurmlab/sequenceserver#520 for details. To activate the widget, add ":databases_widget: tree" to your SequenceServer config file (which is ~/.sequenceserver.conf by default). The tree widget additionally allows linking databases to external page (how to do so will be documented on the website in due time)
• We have introduced a new num_jobs setting. This is the number of concurrent BLAST searches that SequenceServer will run - the default value is 1. This is distinct from num_threads, which is passed to BLAST, and is the number of threads that each BLAST job will use.