return a list with selectors as keys, otherwise the main menu won't
link the active revision, but instead use the main branch
* changelog.html, tree.html: shorten the branch / tag output a bit
(still ugly to have a fixed output like this, though), link tags
by their selector, no longer by their revision ID. We loose some
flexibility here, since tags could actually mark different
revisions, which are now ignored
* IDF_Project: optionally give getSourceAccessUrl() a commit argument, so a particular VCS module can determine a subset of revisions to pull for the specific revision which is browsed
* IDF_Scm_*: add the argument null'd for all VCS; implement a branch lookup for monotone
* tree.html: display the correct branch to clone under each revision tree
