enhance documentation

- flatten hierarchy (some links do not work when using folders)
+ fix a bug with the redorder flag in Override
+ allow removal of parameters
+ clean description using inspect.cleandoc

Change-Id: I3dde4f4cb29c46e8a21014f1fad7aa3ad610a1bf

doc/source/index.rst

@@ -1,18 +1,16 @@
-Welcome to the FRAPPY documentation!
-====================================
+Frappy Programming Guide
+========================
 
 .. toctree::
    :maxdepth: 2
 
-   tutorial/tutorial
-   server
-   framework
-   facility/index
-
-
-Indices and tables
-==================
+   introduction
+   tutorial
+   reference
+   secop_psi
+   secop_demo
+   secop_mlz
+   secop_ess
 
 * :ref:`genindex`
-* :ref:`modindex`
-* :ref:`search`
+