use Perl

I haven't had much time to work on AI::Prolog last week, so this week's release is primarily ensuring that every class at least has stub documentation and I've added about 100 tests to the distribution. No new features at this time aside from a slightly improved aiprolog shell, though I just realized that I left "trace" mode on in the shell. Now I need another release just to disable that. Whoops!.

To do that yourself, in the aiprolog shell program, comment out the following line:

AI::Prolog::Engine->trace(1);

Alternatively, you can set it to a false value. However, if you leave it set to a true value it will show you the steps it's taking to satisfy a goal. This can be very useful for debugging.

Update: And while we're at it, how did I jump from 0.04 to 0.5 without noticing? I was striving for a 0.1 release where I would be feature complete and and working towards a beta, but I appear to have fat-fingered the version. Admittedly I could try and justify this by pointing out that my major reworking of the internals with the 0.5 release justified the jump since that reworking was part of the long-range plan. However, that would be a lie. I just biffed it :/ Now I'm on 0.6 and the code should not be there. It's not far enough along to warrant that.