PSR2, tests and refactor

[rodolfobandeira]

Hi there,

• This pull request suggests PSR2 as code style for this project;
• Add composer.lock so all contributors stays on the same versions;
• Refactor setShopName with just one regex;
• Add PHPCS/PHPCBF on composer's development mode;
• Add test instructions on readme for phpunit and phpcs;
• Rename readme.md to README.md to maintain github's pattern;

Please share your thoughts.

[rodolfobandeira]

cc @joshubrown

[joshubrown]

This looks good - thanks again @rodolfobandeira! We added MIT license info to the the source files. Would you mind rebasing to include these changes?

[rodolfobandeira]

Thank you, @joshubrown

Rebased from the latest master.