tutorial update and X observer

GPy/kern/parts/rbf.py

@@ -65,7 +65,6 @@ class RBF(Kernpart):
                               'extra_link_args'   : ['-lgomp']}
     
     def on_input_change(self, X):
-        import pdb;pdb.set_trace()
         self._K_computations(X, None)
     
     def update_lengthscale(self, l):

doc/tuto_creating_new_kernels.rst

@@ -73,6 +73,8 @@ precomputations for the kernel.
     def parameters_changed(self):
         # nothing todo here
 
+
+
 .. **_get_params(self)**
 
 .. The implementation of this function in mandatory.