Try to figure why some metadats doesn’t appear with ViewMetadatas vim command
	modifié:         plugin/vepub_metadata.py
	modifié:         plugin/vepub_metadata.py
	modifié:         plugin/vepub_metadata.py
	modifié:         plugin/vepub_metadata.py
	modifié:         plugin/vepub_metadata.py
	modifié:         plugin/vepub_metadata.py
language tag is supposed to be unique
	modifié:         plugin/vepub_metadata.py
Docstrings
	modifié:         plugin/vepub_metadata.py