Added composer.json with install/update scripts.
Merge pull request #202 from WordPress-Coding-Standards/develop

2014-10-09 Release
Provide instructions for opening PRs, naming convention for branches
Update CONTRIBUTING.md to indicate master...develop PR
Add Branches heading
Specified MIT license in composer.json.
Specified stable version range in composer.json, starting with required relative paths support.
Merge pull request #195 from Rarst/composer-reboot

Added composer.json with install/update scripts.
Merge branch 'master' into develop