Adding average distance between trees as cluster quality metric.
Add cluster parameters average weighted by cluster size to summary table.
Fixing average distance within cluster calculation for clusters of size 1.
Create metric wrapper object only once when metric module is created.
Rename treecmp4Gui -> treecmp.
Update treecmp package with new version from dambo2013
Adding Flow Cluster/Split, Geodesic and Weighted Matching Cluster metric.
Add nodal/nodal splitted L1/L2 metrics.