Allow URLs that don't contain a path
Merge branch '2.3' into 2.4

* 2.3:
  [Console]Improve formatter for double-width character
  Lower mbstring dep, remove it for Yaml and CssSelector components
  [Security] Add check for supported attributes in AclVoter
  [Form] Fixed TrimListenerTest as of PHP 5.5
  Added more IDE links
  [DependencyInjection] Fix parameter description in ConfigurationExtensionInterface
  [Finder] fixed typehint of the Finder::addAdapter() method
  [TwigBridge][Transchoice] set %count% from the current context.
  [DependencyInjection] Fix travis unit tests
  Update PHPUnit before run
  [Validator] fixed wrong test
  [WebProfilerBundle] added test case for #10773
  [WebProfilerBundle] fixed profiler homepage, fixed #10806
  [WebProfilerBundle] Added test case for #10806
  changed travis to run on the nightly builds of HHVM until everything gets stable
  Fixed issue #5427
  Allow URLs that don't contain a path

Conflicts:
	.travis.yml