Kernel: implement Symfony Kernel methods.

Implement a more sophisticated Kernel that is mainly copied from the
Symfony HttpKernel Kernel. This way we can properly add Symfony2 Bundles
to Fork CMS without needing to write our own connectors.
Kernel: remove unused bundles.
Composer: update dependencies.
Core: replace email address.

Replace jelmer.snoeck@netlash.com to jelmer@siphoc.com.
Config: make proper use of the config.
Kernel: add extra file loaders.
Kernel: remove comments.
Tools: add cache remover.
Installer: remove container registration.

We're doing this when we're booting our application.
Installer: escape @ sign for config parameters.
Parameters: set base file in proper position.
Composer: add after update script.

This way, if you include a new bundle or something like that, the cache
will be cleared automatically.
Merge branch 'master' into migration-symfony-bundles

* master: (56 commits)
  remove references and comments copied from the blog module
  Removed "Thx to XYZ from CHANGELOG.md"
  Preparing for release.
  Bump Minify version number
  Minify is now installed with Composer
  Bugfix: Used correct path for checking if Fork is installed.
  API: add proper response upon trying to login with a non-existing account
  Installed.txt is created in /install/cache/
  fix typo
  don't remove the installed.txt file
  Removed useless code
  updated composer message
  Changelog updated
  Remove html entities out of header
  Bugfix: CKEditor didn't shown when using Chinese as interface language.
  Updated changelog
  Proper identation
  Hide iframe added by Pinterest
  Cleanup
  Updated changelog
  ...

Conflicts:
	app/AppKernel.php
	composer.json
	composer.lock
	tools/remove_cache
Install: do proper path check.
Tools: do not remove install cache.
Core: add monolog bundle.
Monolog: add basic action loggin.
Core: replace Spoon logging by Symfony logging.
Logger: add more logging.
Backend: action: use proper indentation.