Added an option to dump the config reference
Fixed use statement conflict
Fixed the feature on Unix systems

The Yaml dumper is quoting values containing a space but not values
without spaces. The default temp folder does not have a space on Unix
systems, while it depends on the user name on Windows.
Removed usage of the deprecated class on Symfony 2.4+
Ensured a consistent default error reporting level for PHP 5.4 and 5.5

E_ALL includes E_STRICT as of PHP 5.5 but it was not the case in PHP 5.3
and 5.4. The default value for the error reporting now includes E_STRICT
for all versions to be consistent.
Add missing info and example blocks to configuration
Optimize core --config-reference
Fix config_reference.feature

Generation of config reference is responsiblity of Symfony2 config component. We trust this guy to
do his job and rely on him. Our responsiblity is just to make sure that we properly call him and
reproduce its entire output to the stdout.
Merge pull request #496 from Behat/feature/config-reference

Config reference feature