add missing ontologies.download key.
Merge pull request #1093 from ontohub/fix_en_yml

add missing ontologies.download key.
fix description-reading for logicgraph-parsing

The characters method can be called multiple times in order to retrieve
the full text (like chunks) so we'll need to concatenate the results.
let description for logicgraph default to nil

This is needed for possible updates of description
on subsequent runs of the logicgraph-parsing.
respect newlines when displaying logic description.