[RELEASE] Clean-Up and Slim Down

Clean-up release. Notice the following breaking changes:

• RenderingContextFixture has been removed (use regular mocking for your tests)
• FileStreamWrapper has been removed (use vfs stream instead)

Changelog:

• [!!!][TASK] Remove FileStreamWrapper
• [TASK] Raise minimum phpunit version
• [TASK] Clean up specific ViewHelper functionality
• [BUGFIX] Streaming scenario creation