Changed ways WORK directories are used (multiple languages don't need multiple downloads):
- All actions before 'build' are going into a language unspecific directory
- only build and the actions after that (all included in 'bam') are going into a language specific directory
- before really starting with actions needed directories are created if needed.
- 'create_dirs' has been split up into 'purge_dirs' and 'create_dirs'
Finish workdir feature: build multiple languages of a map without multiple downloads