* erepo: load external repos directly from git tree
* erepo: add fetch_external
* remote/RepoTree: add callback for keeping track of download counts when
saving tree to cache
* repo: use erepo.fetch_external() in repo.fetch()
* erepo: return cache save_infos in fetch_external
* DependencyRepo: use erepo.fetch_external and cache.checkout instead of
pull_to
* erepo: remove pull_to
* DvcTree: support granularity for isdir()
* DvcTree: fix indentation bug
* RepoTree: add copytree() method
* LocalRemote: use working tree for local cache walk_files
* repo: state should be noop for GitTree based erepos
* erepo: add get_external()
* test_get: remove unneeded caplog check
* erepo: add get_rev()
* tests: fix erepo test bug
* ls: use RepoTree
* remote: support trees in _collect_dir
* remote: support trees in get_dir_checksum
* RepoTree: fix dir_cache relpaths in windows
* remote: fix duplicated fetch bug
* utils: don't skip md5 dos2unix check for git blobs
* otherwise md5 checksums will not match when comparing git version to
cached filesystem version on windows