Refactor tester for more events

The tester objects is now passed to the test constructor rater than to the test methods to be closer to Aria Template implementation.
It now also raises the events
* begin before running all test methods
* before_X after_X before and after each test method
* end after the end of all tests

This allows to deals with errors in the test constructor
Classes without $classpath

Aria templates allows to define classes by mean of $class and $package