Add important comment for the case that an remote host key change:
'git pull' handles the issue itself, and continues to pull the repository
using the ssh-key provided in the .keys/ directory.
bool branchExistsRemotely();
Check if branch exists in remote customer-repository.
bool branchExistsLocally();
Check if branch exists locally in customer-repository.
bool gitPullNewBranches();
In case the remote branch exists, but not the corresponding local one,
then fetch the remote-branch.
