Merge branch '2.1'

* 2.1:
  [Yaml] fixed default value
  Added Yaml\Dumper::setIndentation() method to allow a custom indentation level of nested nodes.
  added a way to enable/disable object support when parsing/dumping
  added a way to enable/disable PHP support when parsing a YAML input via Yaml::parse()
  fixed CS
  [Process] Fix docblocks, remove `return` from `PhpProcess#start()` as parent returns nothing, cleaned up `ExecutableFinder`
  fixes a bug when output/error output contains a % character
  [Console] fixed input bug when the value of an option is empty (closes #6649, closes #6689)
  [Profiler] [Redis] Fix sort of profiler rows.
  Fix version_compare() calls for PHP 5.5.
  Removed underscores from test method names to be consistent with other components.
  [Process] In edge cases `getcwd()` can return `false`, then `proc_open()` should get `null` to use default value (the working dir of the current PHP process)
  Fix version_compare() calls for PHP 5.5.
  Handle the deprecation of IntlDateFormatter::setTimeZoneId() in PHP 5.5.
  removed the .gitattributes files (closes #6605, reverts #5674)
  [HttpKernel] Clarify misleading comment in ExceptionListener

Conflicts:
	src/Symfony/Bundle/WebProfilerBundle/Resources/views/Profiler/toolbar_style.html.twig
	src/Symfony/Component/Form/Tests/Extension/Core/Type/DateTimeTypeTest.php
	src/Symfony/Component/Form/Tests/Extension/Core/Type/TimeTypeTest.php
	src/Symfony/Component/Form/Tests/Util/PropertyPathTest.php
	src/Symfony/Component/HttpKernel/Profiler/RedisProfilerStorage.php
	src/Symfony/Component/Process/Process.php