Move files to CSSc subfolder

Moved files to CSSc subfolder in order to match the namespace in the php
script.
Add LanguageGuesser class

The LanguageGuesser will be our feature of stylesheet code type guessing.

The user can input code with type CSSc\Language::GUESS and our compiler
will know what to do.

It is important, however, to keep in mind this method is not perfect and
may pick the wrong language occasionally. Use with caution!