Feature/fix imports

[sshort]

Fixed imports by 1) don't write interface class file during parseInterface, but save all the info to a definitions array. 2) Track the structs created in each package in class variable structPackages. 3) After xml has been parsed, write out all the interface classes from the definitions, using the packages saved in 2) to create the import statements.

All the firewalld objects provided earlier now compile cleanly. The code is not that elegant, but since you are re-visting this area anyway...

[hypfvieh]

Could you please change the scope of logback back to "test" or to "runtime". I don't want to force the user to use logback, so we should avoid compile time dependency on it.