Use Fig standards coding style, add composer.json and clean the repo

Use Fig standards (PSR-0, 1 and 2)
move php files to "lib/Testify"
add composer.json
add a simple "test.php"
add .gitignore
add alias "__invoke()" method with "run()"
Update Testify class and the readme

Update Testify class with PSR specifications, force Closure type for
callback and add more informations to the readme
Update and rename Readme.md to README.md
Merge pull request #15 from BafS/master

Some updates for testify !