* 2.8: (22 commits)
[Form] fixed BC-break on grouped choice lists
[WebProfilerBundle] add import for Twig macro
made Symfony compatible with both Twig 1.x and 2.x
[VarDumper] Add caster for pgsql resources
[Debug/VarDumper] minor cleanups
[Form] only use PropertyPath if not already callable
[Form] fix reworked choice list phpdoc
[DoctrineBridge][Form] Add old tests to legacy group
Fixed warning when command alias is longer than command name
removed _self usage when not needed
Add support for target attributes.
Implement the support of timezone objects in the stub IntlDateFormatter
typofix - https://github.com/vlajos/misspell_fixer
make doctrine mappings compiler pass exception message more understandable
fix debug-ext 003.phpt
[Yaml] Nested merge keys
[FrameworkBundle] [Command] removed unused variable.
[FrameworkBundle] fix serializer config check
[Debug] Enhance DebugClassLoader performance on MacOSX
Add support for variadic arguments in the GetSetNormalizer
...
To let opcode caches optimize cached code, the `PHP_VERSION_ID`
constant is used to detect the current PHP version instead of calling
`version_compare()` with `PHP_VERSION`.
