Always setting the 'IgnoreBranches' parameter to a new repository
Detect 'IgnoreBranches' setting value to set (for existing repository)

when the value of the setting is not set
and depending of the number of Tfs remotes initialized
if at least 2 tfs remotes, then we want to support branches
otherwise, ignoring them...
Add a message to warn the user of the choice made
Merge pull request #674 from pmiossec/better_branch_management_in_existing_repositories

Better branch management in existing repositories