Redirect mnapoli.fr/PHP-DI/ to php-di.org
Implemented a new container definition for reading environment variables.
Fixed documentation that was still for v3
Added explicit testing of PHP 5.3.3
Removed useless symfony/yaml dependency (duh…)
Added PHP 5.3.3 support by fixing a bug that would only appear with that version
Merge pull request #178 from mnapoli/php-5.3.3-support

PHP 5.3.3 support
Added test for DI\env() with null default value.
Implemented dumper for EnvironmentVariableDefinition.
Updated the .gitignore
Merge branch 'master' into 4.3
Merge branch 'env' of github.com:jmalloc/PHP-DI into 4.3
Tiny change in the environment variable dumper