allow TraceableEventDispatcher to reuse event instance in nested events
updated VERSION for 2.3.8
bumped Symfony version to 2.3.9
Merge branch '2.3' into 2.4

* 2.3: (31 commits)
  Fix parent serialization of user object
  [DependencyInjection] fixed typo
  add memcache, memcached, and mongodb extensions to run skipped tests
  [DependencyInjection] Fixed support for backslashes in service ids.
  fix #9356 [Security] Logger should manipulate the user reloaded from provider
  [BrowserKit] fixes #8311 CookieJar is totally ignorant of RFC 6265 edge cases
  [HttpFoundation] fixed constants that do exist in 2.3 (only in 2.4)
  fix 5528 let ArrayNode::normalizeValue respect order of value array provided
  fix #7243 allow 0 as arraynode name
  Fixed issue in BaseDateTimeTransformer when invalid timezone cause Transformation filed exception (closes #9403).
  BinaryFileResponse should also return 416 or 200 on some range-requets
  Do normalization on tag options
  bumped Symfony version to 2.3.9
  updated VERSION for 2.3.8
  update CONTRIBUTORS for 2.3.8
  updated CHANGELOG for 2.3.8
  [Filesystem] Changed the mode for a target file in copy() to be write only.
  [Console] fixed CS
  fixed TableHelper when cell value has new line
  Improved and fixed grammar mistakes. Added pluralized messages
  ...

Conflicts:
	src/Symfony/Component/BrowserKit/Cookie.php
	src/Symfony/Component/HttpKernel/Kernel.php
	src/Symfony/Component/Routing/Matcher/UrlMatcher.php