criton v2.0.0

feature

• (package) sinon v7.1.1
• (package) drop support of node < 6
• (criton) es2015-ify
• (package) eslint-plugin-node v8.0.0
• (package) add eslint
• (package) nyc v13.0.1
• (package) nyc v12.0.2
• (package) sinon v6.0.0
• (package) sinon v5.0.3
• (package) sinon v4.0.0
• (package) coveralls v3.0.0
• (package) sinon v3.0.0
• (package) nyc v11.0.2
• (package) sinon v2.1.0
• (package) nyc v10.0.0
• (package) nyc v9.0.1
• (package) nyc v8.1.0
• (package) nyc v7.0.0
• (package) jscs v3.0.1
• (package) ~ -> ^
• (npmignore) add