Use type(obj).__name__ to determime logfile type

Previously statmech.py used `isinstance(x, GaussianLog, QchemLog, MolproLog))`
when determining if the logfile has the proper methods implemented.
This may cause issues when adding more subclasses, if these lines
are not properly modified. This commit reduces that potential error
by replacing that command with

`isinstance(x, Log) and type(obj).__name__ != 'Log'`

arkane/statmech.py

@@ -307,9 +307,9 @@ def load(self, pdep=False, plot=False):
                                  '{1!r}.'.format(self.modelChemistry, path))
         e0, e_electronic = None, None  # E0 = e_electronic + ZPE
         energyLog = None
-        if isinstance(energy, Log) and not isinstance(energy, (GaussianLog, QChemLog, MolproLog)):
+        if isinstance(energy, Log) and type(energy).__name__ == 'Log':
             energyLog = determine_qm_software(os.path.join(directory, energy.path))
-        elif isinstance(energy, (GaussianLog, QChemLog, MolproLog)):
+        elif isinstance(energy, Log) and type(energy).__name__ != 'Log':
             energyLog = energy
             energyLog.path = os.path.join(directory, energyLog.path)
         elif isinstance(energy, float):
@@ -333,13 +333,13 @@ def load(self, pdep=False, plot=False):
             statmechLog = local_context['frequencies']
         except KeyError:
             raise InputError('Required attribute "frequencies" not found in species file {0!r}.'.format(path))
-        if isinstance(statmechLog, Log) and not isinstance(energy, (GaussianLog, QChemLog, MolproLog)):
+        if isinstance(statmechLog, Log) and type(statmechLog).__name__ == 'Log':
             statmechLog = determine_qm_software(os.path.join(directory, statmechLog.path))
         else:
             statmechLog.path = os.path.join(directory, statmechLog.path)
         try:
             geomLog = local_context['geometry']
-            if isinstance(geomLog, Log) and not isinstance(energy, (GaussianLog, QChemLog, MolproLog)):
+            if isinstance(geomLog, Log) and type(geomLog).__name__ == 'Log':
                 geomLog = determine_qm_software(os.path.join(directory, geomLog.path))
             else:
                 geomLog.path = os.path.join(directory, geomLog.path)
@@ -487,7 +487,7 @@ def load(self, pdep=False, plot=False):
                         # the symmetry number will be derived from the scan
                         scanLog, pivots, top, fit = q
                     # Load the hindered rotor scan energies
-                    if isinstance(scanLog, Log) and not isinstance(energy, (GaussianLog, QChemLog, MolproLog)):
+                    if isinstance(scanLog, Log) and type(scanLog).__name__ == 'Log':
                         scanLog = determine_qm_software(os.path.join(directory, scanLog.path))
                     scanLog.path = os.path.join(directory, scanLog.path)
                     if isinstance(scanLog, (GaussianLog, QChemLog)):