Reuseable ABAP functionality

For use with latest https://github.com/abaplint/transpiler

• To ensure the stuff works you need to have nodejs installed
• run npm install
• to run linter - npm run lint
• to run tests - npm run unit
• to run all together - npm test (please beware that both linter and test should pass for PR to be accepted)
• to add new functionality please cover it with unit tests appropriately

For example cl_abap_datfm.clas.abap implements the cl_abap_datfm class. The cl_abap_datfm.clas.testclasses.abap defined unit tests for it. So all like in real ABAP :)