Separate super and sub classes' snippets

The way the snippet was set (one only snippet for both
super and sub classes) prompted the creation of super classes
of the kind:

class ClassName(object):
      '''Doc'''
      def __init__(self):
      	  super().__init__()
	  ...

calling the method super() in a subclass of 'object'
rises the 'useless-super-delegation' warning from
pylintrc.
This can be avoided by creating a separated snippet
for subclasses, in which the method super() has an
usefull effect.

Signed-off-by: Gustavo Gurgel <gukgurgel@gmail.com>

snippets/python-mode/class

@@ -1,13 +1,12 @@
 # -*- mode: snippet -*-
-# name: class(parent): ...
+# name: class: ...
 # key: class
 # group: Definitions
 # --
-class ${1:ClassName}(${2:object}):
-    """${3:Documentation for $1}
+class ${1:ClassName}:
+    """${2:Documentation for $1}
 
     """
-    def __init__(self${4:, args}):
-        super().__init__($5)
-        ${4:$(elpy-snippet-init-assignments yas-text)}
+    def __init__(self${3:, args}):
+        ${3:$(elpy-snippet-init-assignments yas-text)}
         $0

snippets/python-mode/sclass

@@ -0,0 +1,13 @@
+# -*- mode: snippet -*-
+# name: sclass(parent): ...
+# key: sclass
+# group: Definitions
+# --
+class ${1:SubClassName}(${2:ParentClass}):
+    """${3:Documentation for $1}
+
+    """
+    def __init__(self${4:, args}):
+        super().__init__($5)
+        ${4:$(elpy-snippet-init-assignments yas-text)}
+        $0