haskell-v0.5: More functions, types and better typesetting.

This version (v0.5) is a big improvement over v0.4.
Among the several changes, are:

* more functions covered;
* added types for functions;
* added examples;
* removed most stuff not in Prelude;
* covering a good part of Prelude;
* new title (better stating the scope of the cheat sheet);
* better typesetting (better column handling).

A minor review of this could be made into a 1.0 version.