Real-time data retrieval and network graph improvements
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* An interface for querying waiting times and barrier free status of nodes in real time from Vienna's Wiener Linien is now available
* graphs generated from ntw objects now have their edges named after the lines connecting the vertices
* graphs can now have waiting times associated as weights with their edges
* route finding now reports back vertices, edges passed and the weight accumulated while doing so
* Utility functions for converting between station names and graph vertices are now available