Judy for Ruby 1.8.6

I ported Judy patch to Ruby 1.8.6. Speedups are comparable to ones in 1.8.5. On benchmarks from YARV (score is mean of 3 middle times from 5 runs):

Benchmark	Speedup
app_answer	1.9%
app_fib	1.3%
app_mandelbrot	4.2%
app_raise	7.1%
app_strconcat	0.3%
app_tak	0.8%
app_tarai	2.7%

Mandelbrot benchmark is obviously significantly improved, as Judy improves instance variable getting/setting a lot, and it uses complex numbers, which are Ruby objects. I'm not really sure why raise is affected so much, but it was consistent accross 5 benchmark runs.

In any case, you can get the patch here.