Update version in package.json to reflect 5.0 release cut

5.0 Release

4.0 Major Release

Incrementing version number in prep for release

Build enhancements

Added React Router

Upgraded to Babel 6, ESLint 2, and more

Upgraded babel-estlint to resolve bug

Generating separate CSS file for prod

Switched wepack devtool setting, linting build scripts, updated docs