0.9.2-beta

• clear occurrences on load new topic
• add snap function for graph nodes
• fetch names for node classification labels
• rework layout
• rework occurences using exist-db kwic module and range index
• add fallback filter_label
• add functionality for Handbuch
• fix occurrences for librettoSources
• add license information
• prevent topic-description in topicsFiltered