Update pubchempy.py

Canonical SMILES and Isometric SMILES are listed as deprecated in favor of SMILES (both stereoscopic and isometric) on the PUG REST documentation.  Added capability to get SMILES string as follows:

def run(Compound_Name):
  compounds = pcp.get_compounds(Compound_Name, 'name')
  for c in compounds:
    print(c.to_dict(properties=['smiles'])['smiles'])

pubchempy.py

@@ -354,6 +354,7 @@ def get_assays(identifier, namespace='aid', **kwargs):
 PROPERTY_MAP = {
     'molecular_formula': 'MolecularFormula',
     'molecular_weight': 'MolecularWeight',
+    'smiles': 'SMILES',
     'canonical_smiles': 'CanonicalSMILES',
     'isomeric_smiles': 'IsomericSMILES',
     'inchi': 'InChI',
@@ -827,14 +828,19 @@ def molecular_weight(self):
         """Molecular Weight."""
         return _parse_prop({'label': 'Molecular Weight'}, self.record['props'])
 
+    @property
+    def smiles(self):
+        """SMILES, with both stereochemical and isotopic information."""
+        return _parse_prop({'label': 'SMILES'}, self.record['props'])
+
     @property
     def canonical_smiles(self):
-        """Canonical SMILES, with no stereochemistry information."""
+        """Canonical SMILES, with no stereochemistry information (deprecated)."""
         return _parse_prop({'label': 'SMILES', 'name': 'Canonical'}, self.record['props'])
 
     @property
     def isomeric_smiles(self):
-        """Isomeric SMILES."""
+        """Isomeric SMILES (deprecated)."""
         return _parse_prop({'label': 'SMILES', 'name': 'Isomeric'}, self.record['props'])
 
     @property