Improve doc

fix #669
A lot of fixes in documentation
Add references to ProGit v2 book
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
Some silly people could add changes when renaming a branch
Detecting an branch rename changeset
Process changeset when with new branch (instead with old one)

Ignore rename changeset when discovered because
we want to process it as a changeset of the renamed branch.

This way, if changes are made (other than the branch renaming),
there will be fetched in TfsHelperBase.GetChangesets()!

Before that change, there would have been not fetched
because the tfs path was the one of the old branch but
the changes belong to the new renamed branch path!
Manage case where the first changeset of a clone is a rename changeset