Merge branch 'master' of git://github.com/LuaDist/luadist-git into update

* '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'
enable boostrapping with Lua5.2
Lua 5.2 boostrapping compatibility

Enable boostrapping with Lua 5.2 but keep code compatible with lua 5.1,
so that luadist-git can be installed with both versions.
Merge branch 'master' into update

* master:
Merge branch 'master' of git://github.com/cyrilRomain/luadist-git into update

* 'master' of git://github.com/cyrilRomain/luadist-git:
  enable boostrapping with Lua5.2
Merged lua-5.2 compatibiliy changes
Added Lua 5.2 compatibility thanks to @cyrilRomain