Port hclust, sub_score_mat and sub_dist_mat from FlyCircuit package
Add test for hclustn
Add plot3d.hclust
Rename hclustn -> nhclust
Fix remaining instances of hclustn_>nhclust
Fix test: hclust's ward method has been renamed

* now called ward.D rather than just ward
Merge branch 'flycircuit_porting'

* flycircuit_porting:
  Fix test: hclust's ward method has been renamed
  Fix remaining instances of hclustn_>nhclust
  Rename hclustn -> nhclust
  Add plot3d.hclust
  Add test for hclustn
  Port hclust, sub_score_mat and sub_dist_mat from FlyCircuit package