More reliable path detection
Merge branch 'master' of git://github.com/LuaDist/luadist-git

* 'master' of git://github.com/LuaDist/luadist-git:
  in case of an unknown command, print what it was...
  tree: add note about architecture
  fix: nil exception on OS specific depends
  tree func.: cache by which module are the dependencies satisfied + further fixes
  todo added
  tree func.: separate cache for dependency information
  'tree' functionality: add caching + some refactoring and fixes
  add config.dep_cache_file
  fix: incorrect handling of OS specific depends in the 'tree' functionality
  prototype 'tree' functionality
  do not require git urls to end with '.git'