Add license header to files

[eriksven]

This is not a technical issue but concerns the license situation of the content in this repository. To make the license more clear and enable license scanning on file level it would be very helpful to have license headers in each file of the repository.

Because of that the Eclipse Project Handbook states:

"Where possible, all source code, property files, and metadata files (including application, test, and generated source code as well as other types of files such as XML, HTML, etc.) should contain appropriate copyright and license notices as well as information on each contribution."

Could you therefore please add license headers, e.g., in the form described in the Eclipse Project Handbook or other Eclipse Projects.