Improve documentation here and there.

* doc/Doxyfile.in: Update to Doxygen 1.8.4
* doc/footer.html: Point to the mailing list.
* doc/mainpage.dox: Point to spot::translator,
and spot::kripke.
* src/ta/tgta.hh: Do not use \emph.
* src/tgba/succiter.hh: Fix rendering of example.
* src/tgba/tgba.hh: Correct documentation.
* src/tgbaalgos/cycles.hh: Improve rendering of
documentation.
* src/tgbaalgos/lbtt.hh, src/tgbaalgos/minimize.hh:
Document missing arguments.

src/tgbaalgos/cycles.hh

@@ -63,11 +63,12 @@ namespace spot
   /// cycle.
   ///
   /// The class constructor takes an scc_map that should already have
-  /// been built for its automaton.  Calling run(n) will enumerate all
-  /// elementary cycles in SCC #n.  Each time an SCC is found, the
-  /// method cycle_found(s) is called with the initial state s of the
-  /// cycle: the cycle is constituted from all the states that are on
-  /// the dfs_ stack after s (including s).
+  /// been built for its automaton.  Calling <code>run(n)</code> will
+  /// enumerate all elementary cycles in SCC <code>n</code>.  Each
+  /// time an SCC is found, the method cycle_found(s) is called with
+  /// the initial state s of the cycle: the cycle is constituted from
+  /// all the states that are on the \c dfs_ stack after \c s
+  /// (including \c s).
   ///
   /// You should inherit from this class and redefine the
   /// cycle_found() method to perform any work you would like to do on

src/tgbaalgos/lbtt.hh

@@ -44,6 +44,8 @@ namespace spot
   ///
   /// \param is The stream on which the automaton should be input.
   /// \param error A string in which to write any error message.
+  /// \param dict The dictionary that should register the BDD variables
+  /// used by the automaton built.
   /// \param env The environment of atomic proposition into which parsing
   ///        should take place.
   /// \param envacc The environment of acceptance conditions into which parsing

src/tgbaalgos/minimize.hh

@@ -127,6 +127,8 @@ namespace spot
   /// \param aut_f the automaton to minimize
   /// \param f the LTL formula represented by the automaton \a aut_f
   /// \param aut_neg_f an automaton representing the negation of \a aut_f
+  /// \param reject_bigger Whether the minimal WDBA should be discarded if
+  /// it has more states than the input.
   /// \return a new tgba if the automaton could be minimized, \a aut_f if
   /// the automaton cannot be minimized, 0 if we do not know if the
   /// minimization is correct because neither \a f nor \a aut_neg_f