ExtensionManager provides clear exception message when exception is not found
Autoloader is now always registered, even if there are no services that depend on it

Fixes #453
Dispatch AfterSuiteAborted event on scenario failure and --stop-on-failure

Closes #482
Merge pull request #492 from Behat/bugfix/quiet-extension-init-failure

ExtensionManager provides clear exception message when exception is not found
Merge pull request #494 from Behat/bugfix/dispatch-suite-on-stop

Dispatch AfterSuiteAborted event on scenario failure and --stop-on-failure
Merge pull request #493 from Behat/bugfix/testwork-autoloader

Autoloader is now always registered, even if there are no services that depend on it
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
Most core extensions are now locked
Fix controller priorities
HookExtension does not need to be an abstract
Merge pull request #497 from Behat/optimization/extensions-lock

Extensions lock and controllers priority optimisation
ContextEnvironmentReader::readContextCallees() has a proper signature