Merge pull request #279 from guillermo-carrasco/master

Invalid cross-device link solved by substituting os.rename by shutil.move
Added test files for the merge_undemultiplexed_stats_metrics tests
Test new functionality merge_undemultiplexed_stats_metrics
Add new functionality merge_undemultiplexed_stats_metrics to merge Undemultiplexed_stats.metrics files
Merge pull request #281 from guillermo-carrasco/demultiplex

Mrege Undemultiplexed_stats.metrics files