Refactored code

Added Response class.
Commented all classes.
Removed unused classes.
- ErrorController class
- Document class
- Logger class (Will be reintroduced later)
PHPUnit preparations
Atom indentation bug
Deprecated RequestEvent class
Update Request class
Update Response class
Update Session class
Update Event class
Introduced AbstractEvent class
Changed NULL to null
Changed self:: to static::
Update Router interface
Update StaticRouter class