Merge pull request #26 from ShoeSizeMe/master

update d3 to 3.4.11
Merge pull request #27 from ShoeSizeMe/master

bump d3 version to 4.3.13
Add license statement to gemspec, fixes #20
Merge pull request #28 from ShoeSizeMe/3.5.2

bump d3 version to 3.5.2
Merge remote-tracking branch 'upstream/master'