provide XMI save options for speeding up serialization
use snapshot version
do not copy lists that are already a copy in SaltAnnotateExtractor
always set SName for SOrderingRelations
avoiding automatic setting of SName
use RelannisNodeFeature instead of 8 single features in order to save Salt processing time
add a way to benchmark the salt mapping
do not use listIterator if not needed and removed uncompileable helper class
do not commit benchmark db
context combobox values are actual integers and don't need to be parsed from strings any longer
allow to filter subgrap query to include only token
allow to only fetch token when doing a subgraph query

This is quite useful for exporters that are only displaying token and don't need the large overhead of other nodes.
display number of already exported items
do not join on metadata in matrix query if no metadata was requested
instance better described
Change annotation key from page -> node_key in pdf visualizer.
Really change the node_key of pdf visualizer mapping.
wrote comments
Update documentation of PDFVisualizer.
fixes #129