Merge pull request #10 from jrdnull/master

Add clock problem
Conform to PSR-2, add Composer/PHPUnit configs

Update Makefile, add SETUP.md
Add PHP CodeSniffer
Use @group annotation to skip tests
Merge pull request #11 from jrdnull/psr2

Conform to PSR-2, add Composer/PHPUnit configs
Add leap problem