[ard] enhanced ard handling and plotting

Conflicts:
	GPy/kern/_src/linear.py
	GPy/models/ss_gplvm.py

GPy/kern/_src/add.py

@@ -14,6 +14,13 @@ class Add(CombinationKernel):
     This kernel will take over the active dims of it's subkernels passed in.
     """
     def __init__(self, subkerns, name='add'):
+        for i, kern in enumerate(subkerns[:]):
+            if isinstance(kern, Add):
+                del subkerns[i]
+                for part in kern.parts[::-1]:
+                    kern.remove_parameter(part)
+                    subkerns.insert(i, part)
+
         super(Add, self).__init__(subkerns, name)
 
     @Cache_this(limit=2, force_kwargs=['which_parts'])
@@ -160,7 +167,7 @@ class Add(CombinationKernel):
             [np.add(target_grads[i],grads[i],target_grads[i]) for i in xrange(len(grads))]
         return target_grads
 
-    def add(self, other, name='sum'):
+    def add(self, other):
         if isinstance(other, Add):
             other_params = other.parameters[:]
             for p in other_params:
@@ -171,5 +178,11 @@ class Add(CombinationKernel):
         self.input_dim, self.active_dims = self.get_input_dim_active_dims(self.parts)
         return self
 
-    def input_sensitivity(self):
-        return reduce(np.add, [k.input_sensitivity() for k in self.parts])
+    def input_sensitivity(self, summarize=True):
+        if summarize:
+            return reduce(np.add, [k.input_sensitivity(summarize) for k in self.parts])
+        else:
+            i_s = np.zeros((len(self.parts), self.input_dim))
+            from operator import setitem
+            [setitem(i_s, (i, Ellipsis), k.input_sensitivity(summarize)) for i, k in enumerate(self.parts)]
+            return i_s