Trace: Use autoloader

[ScreamingDev]

Rollover this issue among releases. This one just keeps track of a bigger process by linking pull requests to it.

Currently some classes are included automagically and some manually.
The manual ones are upsetting when you want to reuse a class in some other context way before such classes exists or have been loaded,
which can't be loaded earlier as they contain logic and other calls beside the class itself.
Simple solution would be an autoloader.

• Remove logic from all class files (only class itself should be in there).

This issue keeps track of refactoring the code so that the already implemented autoloader can be used properly. Let's start a list and edit important things to it that come up during this process:

• We deal with namespaces here so we no longer support PHP 5.2 .