Fix for #441

Update requirements

Consistent api with ud

Fix for #436

Release 2.0.28

Support for LRG 1.9

- Switch to new LRG location (fix for #447).
- Extract only the gene name from the `updatable` section.
- Fix for LRG transcripts with no coding region.
- Adapted LRG examples on the website.
- Extract the annotation set based on attribute type.
- More informative error message (part of #135).
- Makes #338 obsolete.

Release 2.0.27

Set default timeout for the batch processor

Large references (chromosomes) slicing

Solves the problem that apperead when a large reference sequence was
requested in combination with slicing: the server returned a 'Bad Gateway'
error or gave an empty or incomplete response.

Make sure getGeneLocation uses standard strategy to select mapping

When multiple mappings available, getGeneLocation now orders by
chromosome name before returning the first mapping, as is standard
for code based on Convertor._get_mapping().

New test case where a gene has mappings to both chromosome X and Y, and
the test verifies that the same mapping is selected in API calls to
both getGeneLocation and numberConversion.