Shed Skin 0.0.5.9

I have just released Shed Skin 0.0.5.9. It's almost where I want it to be
for 0.0.6. What remains to be coded is some kind of connection to the
standard library (probably a simple one at first: working only for
'opaque handlers'). I also want to improve cases where ints and floats
are mixed, since this is quite common. Some major changes:

-basic exception handling

(support for custom ones, and for some builtins such as ValueError,
KeyError and AssertionError; this will allow for implementation of
iterator objects later on)

-some basic inheritance

(no multiple inheritance yet, or weird stuff; this enabled me to add
the 340-line pygmy raytracer to the test set. it becomes about 40
times faster here..)

-keyword arguments

(this has not been tested very well yet - let me know about any problems)

-many missing minor 'set' features, thanks to reports by bearophile

(it should be practically complete now. the whole set of builtins is
nearing completion :D time to start optimizing stuff..)

-many, many bugfixes again, again mostly thanks to bearophile

I added four new 'big' programs to the test set that (with some minor
modifications) work now: a tic-tac-toe player for arbitrary size
boards, a simple genetics algorithm, a linear algebra program and the
mentioned raytracer. Finally, the README has been improved again,
though it's still pretty bad. After the release of 0.0.6 I plan to
create a web site with performance comparisons between CPython, Psyco
and Shed Skin (perhaps even PyPy :P), because quite some interesting
programs compile now, and Shed Skin is usually a lot faster than Psyco, except when Python builtins are the bottleneck. I guess some more STL magic is required here..

Let the small code fragments that fail flowing!