use 'ligand' property in the conservation example

examples/demos/conservation.py

-from ost.seq import alg
 scene.RemoveAll()
 #-------------------------------------------------------------------------------
 # Loading structure and alignment
 #-------------------------------------------------------------------------------
 m=io.LoadPDB('data/sh2.pdb')
-mp=m.Select('ishetatm=false')
+mp=m.Select('ligand=false')
 aln=io.LoadAlignment('data/sh2.aln')
 aln.AttachView(0, mp)
 aln.SetSequenceOffset(0, 1)
@@ -13,7 +12,7 @@ aln.SetSequenceOffset(0, 1)
 # First we set all properties to zero, then let alg.Conservation assign the
 # conservation scores to the residues
 #-------------------------------------------------------------------------------
-alg.Conservation(aln)
+seq.alg.Conservation(aln)
 
 #-------------------------------------------------------------------------------
 # Setup Graphical Objects for Rendering
@@ -25,7 +24,7 @@ scene.Add(gs)
 scene.Add(g)
 scene.CenterOn(g)
 
-s.Attach(mp.Select('ishetatm=false'), 8.0)
+s.Attach(mp.Select('ligand=false'), 8.0)
 
 gr=gfx.Gradient()
 gr.SetColorAt(0.0, gfx.Color(0.1, 0.1, 0.8))
@@ -34,10 +33,10 @@ gr.SetColorAt(1.0, gfx.Color(0.8, 0.1, 0.1))
 gs.ColorBy('cons', gr, 0.8, 1.0, 
            mol.Prop.Level.RESIDUE)
 g.SetRenderMode(gfx.HSC, 
-                m.Select('ishetatm=false'))
+                m.Select('ligand=false'))
 g.SetRenderMode(gfx.CUSTOM, 
-                m.Select('ishetatm=true'))
-g.SetColor(gfx.YELLOW, 'ishetatm=true')
+                m.Select('ligand=true'))
+g.SetColor(gfx.YELLOW, 'ligand=true')
 
 #-------------------------------------------------------------------------------
 # Create alignment viewer and show it on the screen

examples/demos/data/sh2.pdb

+HET    AYI  A   1      37 
 HELIX    1   1 PRO A   66  LYS A   76  1                                  11    
 HELIX    2   2 SER A  127  HIS A  135  1                                   9    
 SHEET    1   A 4 PHE A  83  GLU A  87  0