Fix shortest absolute paths from cwd to classmap path
Documentation for satis-based downloads.
Engrish is hard.
Merge pull request #1747 from till/topics/satis-downloads-docs

Documentation for satis-based downloads.
Fix handling of branches with slashes, fixes #1748
Use cross-platform absolute path check
Cache getcwd() result
Merge pull request #1743 from sandermarechal/abs-path

Fix shortest absolute paths from cwd to classmap path