fixed tempermental samples and updated to use AMD

upgraded d3Layer.js to use AMD
this resolved the 'multiple define' errors that sometimes inhibited existing samples from loading properly
updated all 3 samples to use AMD as well.
for some reason, upgrading past version 3.6 of the jsapi caused some funky display issues during transitions (i'll investigate further)

let me know what you think
http://jgravois.github.io/esri-d3/index.html
http://jgravois.github.io/esri-d3/rules.html
http://jgravois.github.io/esri-d3/mlb.html