update templating guide documentation
update according to comments
adjust after feedback from mvriel
Allow symfony/event-dispatcher > 2.1.x

This enables having phpDocumentor as a requirement in a symfony 2.2
application.
The API for EventDispatcher did not change between 2.1 and 2.2
The documentation states that relative paths in the configuration file
are handled with the current working directory as root. This has been
changed in an earlier commit to use the configuration file as root
location.
Merge branch 'develop' of github.com:phpDocumentor/phpDocumentor2 into develop
Merge pull request #801 from tommygnr/allow-symfony-2.2

Allow symfony/event-dispatcher > 2.1.x
Merge pull request #728 from dbu/template-doc-updates

update templating guide documentation