v2.4.0
Merge branch 'release/2.4.0' into production
Merge tag 'v2.4.0'

2.4.0

 * Implement shorthand notation for middleware paths (Raymond Feng)

 * Load middleware and phases from `middleware.json` (Miroslav Bajtoš)

 * Add jscs style check, fix violations found (Miroslav Bajtoš)

 * Clean up .jshintrc (Miroslav Bajtoš)

 * Use `chai` instead of `must` (Miroslav Bajtoš)