Move each class to separate file

This pull request updates file structure to make the repo ready to be distributed as package.

Files now reside in a namespaced folder with accordance to PSR-0. This makes it possible to be autoloaded by composer generated autoloader.

Code style standards (PSR-1, PSR-2) were also applied.

A brief attempt was taken to replace LogDebug class with PSR-3-compliant LoggerInterface, but it wasn't carried out. Still it is a beginning.