added a node about HTML extension in readme
[CssSelector] tweaked README file (closes #8287)
Merge branch '2.3'

* 2.3: (33 commits)
  [Form] fixed INF usage which does not work on Solaris (closes #8246)
  Fix grammar
  Removed PHP 5.5 from the allowed failures.
  [Intl] Fixed tests failing on PHP 5.5
  bumped Symfony version to 2.2.4
  updated VERSION for 2.2.3
  update CONTRIBUTORS for 2.2.3
  updated CHANGELOG for 2.2.3
  [DependencyInjection] Replaced try/catch block with an @expectedException annotation in a test.
  [CssSelector] tweaked README file (closes #8287)
  added a node about HTML extension in readme
  [Console] Fixed the table rendering with multi-byte strings.
  Feature/fix unit tests
  [Process] Disable exception on stream_select timeout
  [HttpFoundation] fixed issue with session_regenerate_id (closes #7380)
  [DomCrawler] added a note about the default charset
  Throw exception if value is passed to VALUE_NONE input, long syntax
  fixed date type format pattern regex
  [Security] fixed usage of the salt for the bcrypt encoder (refs #8210)
  [FrameworkBundle] tweaked previous merge (refs #8242)
  ...

Conflicts:
	src/Symfony/Component/HttpKernel/Kernel.php