redesign of parallel background compilation without clones

- no clones any more, existing jobs are directly linked
- the whole require command is processed by coqdep to determine
  the required files, this fixes #352
- the require commands are a separate kind of jobs, because they
  do not need to get compiled
- queue items are only stored in require jobs and file jobs can
  not have a queue dependency, this simplifies the logic

0 files changed, 0 insertions, 0 deletions