Remove proper files in acceptance tests initialisation.
Added two acceptance tests for digest copy: one if the file is there and is correct, and one if it's there but different.
Add acceptance tests for digest copy_from with server-side connection.ip expansion.
Just stylistic/performance changes, functionally same code.
Fix the MD5 protocol command.

Enforce proper access controls. Expand shortcuts in new protocol. Expand
special variables (ip, hostname, key) as well. Implement acceptance tests
checking them.
Merge pull request #1700 from jimis/shortcut_always_copies-4698

redmine 4698, 5638 and related tickets