Fl_Timeout: Remove compiler warning [-Wclass-memaccess]

Also: fix doxygen warning

src/Fl_Timeout.cxx

@@ -319,7 +319,7 @@ Fl_Timeout *Fl_Timeout::get(double time, Fl_Timeout_Handler cb, void *data) {
 #endif
   }
 
-  memset(t, 0, sizeof(*t));
+  t->next = 0;
   t->delay(time);
   t->callback = cb;
   t->data = data;

src/Fl_Timeout.h

@@ -146,8 +146,6 @@ protected:
     used like a stack (last in, first out).
 
     \see Fl_Timeout::push()                 Member function (method)
-    \see Fl_Timeout *Fl_Timeout::pop()      Static function
-    \see Fl_Timeout *Fl_Timeout::current()  TStatic function
   */
   static Fl_Timeout *current_timeout;   // list of "current" timeouts