Improve graph library

[sunxd3]

No description provided.

[github-actions]

BridgeStan not found at location specified by $BRIDGESTAN environment variable, downloading version 2.5.0 to /home/runner/.bridgestan/bridgestan-2.5.0
Done!
Model dogs produces error: ErrorException("log_density() failed with exception: Exception: bernoulli_lpmf: Probability parameter is inf, but must be in the interval [0, 1] (in '/home/runner/work/JuliaBUGS.jl/JuliaBUGS.jl/benchmark/stan/bugs_examples/vol1/dogs/dogs.stan', line 37, column 6 to line 38, column 62)\n")

Model	Parameter Count	Data Count	Stan Density Time (µs)	Stan Density Gradient Time (µs)	JuliaBUGS Density Time with Graph Walk (µs)	JuliaBUGS Density Gradient Time with ReverseDiff.jl(compiled tape) (µs)
rats	65	150	5.4162	8.07867	6753.1	96.0845
pumps	12	10	1.00566	1.38073	161.601	6.9255
dogs	2	720	NA	NA	3228.93	145.362
seeds	26	21	2.52836	3.33622	620.068	20.539
surgical_realistic	14	12	1.26626	1.64028	214.035	9.16033
magnesium	108	96	10.5095	12.1525	9221.59	82.794
salm	22	18	2.35442	3.21389	467.698	13.921
equiv	15	20	2.6279	3.47025	348.721	16.44
dyes	9	30	1.00397	1.32614	232.294	13.34
stacks	6	21	1.1762	1.679	250.102	15.138
epil	303	236	33.062	38.663	63853.1	267.179
blockers	47	44	3.22711	3.75843	1923.16	31.439
oxford	244	240	16.17	18.835	47033.3	193.145
lsat	1006	5000	176.45	219.549	2.98518e6	1712.56
bones	33	422	73.256	90.819	12674.3	199.979
mice	20	65	7.27625	9.60133	1005.72	41.838
kidney	64	58	10.6095	16.301	3619.28	75.26
leuk	18	714	20.448	26.9	9476.29	217.075
leukfr	40	714	23.765	31.87	18589.4	284.021

[sunxd3]

This has become a monstrosity -- I have been using it as a test field.
It will be broken down and introduce into master gradually in the following days.