In 1.4 there can be more than one repository for a project

We want to handle this in a nice way, thus we enable posibility to
update "default", "specific" and "all" git repos (default might or might
not be a git repo, so we'll have to handle that as well)

To update a specific repo, add parameter "repository_id=NN" to the query
string. to update all repos, add "update_all=yes"