Pylint Fixes

Update our version of pylint to use the latest version and update the
codebase to comply with the majority of the updates.

For now disable the additional checks for `super-with-arguments`,
`useless-object-inheritance`, `raise-missing-from`, `no-else-raise`,
`no-else-break`, `no-else-continue` to be consistent with the existing
codebase.

wa/framework/plugin.py

@@ -157,6 +157,7 @@ class Alias(object):
                 raise ConfigError(msg.format(param, self.name, ext.name))
 
 
+# pylint: disable=bad-mcs-classmethod-argument
 class PluginMeta(type):
     """
     This basically adds some magic to plugins to make implementing new plugins,
@@ -367,7 +368,7 @@ class Plugin(with_metaclass(PluginMeta, object)):
         self._modules.append(module)
 
     def __str__(self):
-        return self.name
+        return str(self.name)
 
     def __repr__(self):
         params = []