test: confirm that js->clj also blows up on cycles

When confronted with a loop, js->clj doesn't try
to do anything fancy.
tests: commented out failing js->clj cycle unit test.
mrhyde: cljs.core.ArrayNodeSeq now a arrayish type

Fixes #1
mrhyde: first version mapping pack->data for clean circle-pack

circle-pack.cljs is finally looking clean, albeit and some
cost. Also, other demos have gotten tremendously slower. So
committing this and then going off to do dective work.
circle-pack: now loading data via working d3.edn call
mrhyde/strokes tweaks for circle-packing side project

cljs.core.List is now arrayish in myhyde land

d3.pack can now take :keyword arguement. Sweet.
circle-packing: removed d3 js from html file.
mrhyde: added benchmarking.

Now we know how bad it is...

/* before mrhyde patches anything...
  (interesting that list is 5-10x slower create/access than vector) */
PreHyde createListObject x 143,412 ops/sec ±0.27% (98 runs sampled)
PreHyde createVectorObject x 18,213,885 ops/sec ±3.08% (94 runs sampled)
PreHyde createMapObject x 7,686,027 ops/sec ±0.20% (98 runs sampled)
PreHyde accessListObject x 6,708,001 ops/sec ±0.15% (98 runs sampled)
PreHyde accessVectorObject x 1,443,918 ops/sec ±0.16% (101 runs sampled)
PreHyde accessMapObject x 18,676,682 ops/sec ±0.61% (95 runs sampled)
/* just for fun, this is native js object access */
PreHyde nativeAccessListObject x 618,921,061 ops/sec ±0.22% (101 runs sampled)
PreHyde nativeAccessVectorObject x 620,857,556 ops/sec ±0.13% (101 runs sampled)
PreHyde nativeAccessMapObject x 621,539,629 ops/sec ±0.14% (94 runs sampled)

/* now we patch */
Now patching and running again... mrhyde-benchmark.html:122
This time init took: 189 unit(s) mrhyde-benchmark.html:127

/* zounds, creation is super slow */
PostHyde createListObject x 512 ops/sec ±4.48% (75 runs sampled)
PostHyde createVectorObject x 28,395 ops/sec ±4.01% (84 runs sampled)
                              ^^^^^^
                              That was 18 million before!
PostHyde createMapObject x 138 ops/sec ±3.76% (67 runs sampled)
                           ^^^
                           That was 7 million before!

/* regular access is maybe a hare slower (I wonder why) */
PostHyde accessListObject x 4,293,689 ops/sec ±0.45% (95 runs sampled)
PostHyde accessVectorObject x 1,132,822 ops/sec ±0.21% (92 runs sampled)
PostHyde accessMapObject x 16,515,281 ops/sec ±2.26% (93 runs sampled)

/* access as js object is fine (better?) for vector, but
   4-5 times slower for list and map */
PostHyde nativeAccessListObject x 985,004 ops/sec ±1.53% (94 runs sampled)
PostHyde nativeAccessVectorObject x 1,435,218 ops/sec ±0.20% (100 runs sampled)
PostHyde nativeAccessMapObject x 3,071,135 ops/sec ±0.24% (97 runs sampled)