[2.6] CS Fixes And Removed An Unused Import
Merge branch '2.6' into 2.7

* 2.6: (25 commits)
  Added information when an error occured during validation of an answer of a question
  Adding note about known BC issues
  Adding note about the PdoSessionHandler BC break
  [Console] fixes some typos and phpdoc.
  fix phpdoc's alignment
  [2.6] CS Fixes And Removed An Unused Import
  Minor phpcs fixes
  [ClassLoader] Fix undefined index in ClassCollectionLoader
  CS fixes
  Revert "minor #12821 Remove deprecated class (MasterB)"
  [2.3] More cs fixes
  Removed unused imports
  CS fixes
  bumped Symfony version to 2.6.2
  updated VERSION for 2.6.1
  updated CHANGELOG for 2.6.1
  bumped Symfony version to 2.5.9
  updated VERSION for 2.5.8
  update CONTRIBUTORS for 2.5.8
  updated CHANGELOG for 2.5.8
  ...

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