Squashed 'vendor/assets/javascripts/d3/plugins/' changes from da342b6..37cf815

37cf815 Include hexbin grid coordinates.
f85f4ce Fix bug with flipped triangles.
9a2ec62 Fix bug.
3b6c089 Fix a bug in hexbin.centers.

git-subtree-dir: vendor/assets/javascripts/d3/plugins
git-subtree-split: 37cf8158cd66f6aa6aba8a8739ae44ed391ca9f8
Merge commit '41d30c586a6ab52e7874a1a1ab16e11d1c776080'

* commit '41d30c586a6ab52e7874a1a1ab16e11d1c776080':
  Squashed 'vendor/assets/javascripts/d3/plugins/' changes from da342b6..37cf815
Bump gem version