Squashed 'vendor/assets/javascripts/d3/plugins/' changes from a3c809c..639c06c

639c06c Add hexbin.centers.
7076ccf Refactor tests to use smash.
694221a Fix for Node 0.10.
057568e Update smash.
cb35708 Remove quincuncial import from index.
c88daab Extract math and hyperbolic functions.
c6fef9f SMASH!
0711bdf Add d3.geo.conicEqualArea.
43b6494 Use node_modules/.bin for binaries.
b4c1e6c Fix Transverse Mercator for |λ|>90° and add tests.
f5dd86c Add d3.geo.transverseMercator to README.
297b304 Fix D3 global in geo.projection test environment.
1bacec4 Update Vows.
bc9c27a Add d3.geo.transverseMercator.

git-subtree-dir: vendor/assets/javascripts/d3/plugins
git-subtree-split: 639c06c61d02d35028749c12b61c3f6c84b17409
Merge commit '5129ddba543ba325b476535e1a21a0b9f27dcbb2'

* commit '5129ddba543ba325b476535e1a21a0b9f27dcbb2':
  Squashed 'vendor/assets/javascripts/d3/plugins/' changes from a3c809c..639c06c
Add gem signature and use secure source