* doc/body.texi: Reorder documentation, making jit_frame
and jit_tramp the lightning response to the need of
trampolines, continuations and tail call optimizations.
A pseudo code example of a factorial function was added.
Also added a section for description of the available
predicates.
* doc/fact.c: New file, implementing a simple example of
a translation of a trivial, recursive, tail call optimization
into lightning calls. This is the conversion to functional C
code of the example in doc/body.texi.
* doc/Makefile.am: Update for the next test case.
