Rewrite with ES2015 module

• Improved: Rewrite with ES2015 module
• Changed: dependencies to devDependencies

v0.1.0

• Added: getWidth and getHeight to get element content size. (Without padding, border and margin.)

v0.0.8

• Update selectivizr source
• Set different compress options for go-native.min.js and go-native.ie8.min.js.

v0.0.7

• Fixed: a gulp-uglify compresser issue.

v0.0.6

• Updated: selectivizr which fixed an issue when using compressed css file.

v0.0.5

• Fixed: an isInViewport issue.

v0.0.4

• Fixed: "documentElement.classList" doesn't exist issue in IE8.
• Removed: version-flags.js

v0.0.3

• Added: ES5 Date (parse, toISOString, toJSON), Object (create, defineProperty, freeze, getOwnPropertyDescriptor, getOwnPropertyNames, getPrototypeOf, isExtensible, isFrozen, isSealed, preventExtensions, seal) extensions.
• Improved: re-organize all the files.

v0.0.2

• Fixed: some syntax issue in ready, append, extend, getOuterWidth, getOuterHeight, getSupportedProp, indexOf, prepend and unwrap.

v0.0.1

• Fixed: a bower.json issue.