v2.0.0

• Mark the package as having no side effects. Thanks, @stof! #61
• Standardize dependencies. d3/d3#3337
• Use explicit files when publishing. d3/d3#3335
• Use exact paths in imports. d3/d3#3265

This release adopts ES2015 language features such as for-of and drops support for older browsers, including IE. If you need to support pre-ES2015 environments, you should stick with d3-axis 1.x or use a transpiler.