Code Generator for Eclipse Code

Add the source foulder to the extension point

Don't try to add jetemplate if jetemplate is null

Added tests for jetemplate with AST, deserialisation of Jetemplate and generation of Template

Implemented generator retrieving through the new method bundle@... but left the old way because it is still used when generationg through the wizard

Implemented the first test case for HeadlessJavaGenerator succesfully

Added todo to fix a validation error

Implemented the headless generator for java classes

Fixed a bug in the validation of the modifiers (missing return)

Added additional test in the validation if wrong arguments for -m od -i are passed.

Completed the validation