added TransliteratorCollection class
fixed tests
added TransliteratorCollection::transliterate() method
default slug generator now transliterates before imploding values
made slug generator stateless
Revert "default slug generator now transliterates before imploding values"

This reverts commit 6e70f35a51176067704449c59705166d85341916.

Conflicts:

	src/Ddd/Slug/Infra/SlugGenerator/DefaultSlugGenerator.php
simplified default generator
Merge pull request #2 from jfsimon/transliterator-collection

added TransliteratorCollection class