Update composer.json
Refactoring Managers
Add background color feature
Refactoring Color managers
Fix bug in mixed output
Fix a few things, extend test coverage
Introduce EscapeAttribute classes
Refactoring color and style with Elements
Fix Style
Add BorderedElement
Add Structure and structure management
Add StructuredElements
Update README.md
Improve .gitignore
Clean codestyle
Fix abstract static methods
Fix unit test
Fix issues found by Scrutinizer
Fix phpDoc
Last fixes by Scrutinizer