Ticket 479

If no records are selected in a results list, the metrics module takes 'config.EXPORT_DEFAULT_ROWS' bibcodes to calculate the metrics on. This is done by capturing the value of the query 'q' parameter in 'views' of the 'bibutils' module and retrieving the bibcodes resulting from this query. This list is then truncated at the above threshold. This way it will be trivial to allow metrics on an entire results set down the line.