no automatic import of lddt, scoring and chain_mapping in mol.alg __init__.py

Reason is that these modules add a dependency on scipy which should be
optional.

modules/mol/alg/pymod/__init__.py

@@ -5,9 +5,6 @@ import ost.mol.alg.trajectory_analysis
 import ost.mol.alg.structure_analysis
 import ost.mol.alg.helix_kinks
 import ost.mol.alg.hbond
-import ost.mol.alg.lddt
-import ost.mol.alg.scoring
-import ost.mol.alg.chain_mapping
 
 # Fills a list of reference clashing distances from a file (requires a path to the file)
 def FillClashingDistancesFromFile(filename):