Reduce the taxa names to 10 characters

src/nejo_idx.py

@@ -49,7 +49,7 @@ class NeighborJoining:
         self._bigmatrix[j,i] = dist
         self._bigmatrix[i,j] = dist
   def taxon_name(self,idx):
-    return self._dm.taxon_name(idx)
+    return self._dm.taxon_name(idx)[:10]
   def numofnodes(self):
     return self._numofnodes
   def num_of_taxa(self):