FIXED: broken instantiation logic of skos_match/5
do not assert status amalgame:imported on preloaded graphs
ADDED: collect reference alignments from multiple graphs that are marked as amalgame:reference in the given Strategy
use all corrpespondences returned by reference_mappings/2 when counting reference statistics, not only manual ones created in amalgame
give new manual evaluation graphs also status amalgame:reference
added status option amalgame:reference to user interface
paint reference graphs dark green in the strategy graph
link to graph list after uploading reference graph