Renamed script bc_measure_distance to bc_measure_beta

...because not all beta diversity metrics are distances
POD update
POD update

...consistent spelling
Fixed typo
Script to measure alpha diversity
Small Alpha diversity test update
Changes file update
Script bc_measure_distance can now be passed a list of metrics to compute
Implemented method get_metacommunity in Bio::Community::Met
More beta diversity tests, and small cleanup
Bio::Community::Gamma can now use the same metrics as Bio::Community::Alpha