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fix #669
A lot of fixes in documentation
Add references to ProGit v2 book
Being able to clone TFS path "$/"
Prevent using 'branch' command when cloned whole repository
Retry after getting a file from TFS if the status is not satisfying

Should improve reliability.
Hope it will fix #444
Encapsulate `NumFailures != 0`.
Merge pull request #664 from pmiossec/improve_reliability_fetch

Retry after getting a file from TFS if the status is not satisfying
Merge pull request #670 from pmiossec/fix_doc

Improve doc
Update release note
Merge pull request #662 from pmiossec/clone_tfs_root

Being able to clone TFS path "$/"