+0.5.? - ?/?/? - ?
+ * refinement of match fixed to prevent useless unfolding,
+ head_beta_reduce is used instead of whd ~delta:true
+
+0.5.1 - 29/5/2008 - minor bug fix release
+ * visualization of inductive types reports the number of fixed parameters
+ * a wrong context was used to refine fixpoints arguments
+ when trying to optimize out the letin (grep for `AvoidLetIn):
+ (let rec f x = Fix... in f t ---> Fix... t)
+ * auto fixed to prefer goals with metavariables to closed ones,
+ added new syntax to specify the universe "auto by t1, t2, ...",
+ updated documentation describing all auto parameters
+ * declarative language syntax and documentation ported to the new
+ auto parameters
+