Slim 3.4.1 released

This releases fixes a infinite loop bug discovered in version 3.4.0 and also adds additional unit tests.

Total issues resolved: 5

• 1866: Error handlers throws exception if content-type not supported
• 1873: Fixing Infinite Loop in Error, Unit Test
• 1874: Use class name constant instead of magic string.
• 1876: Test to check if half valid content type returns default
• 1877: Mock available contentTypes to make test run as it should