accept as graph even detached roots
delete wip comments and tags
new generic static method to search and return elements in sorted lists
the semantic of timelines changed
added oldest timestamp
add methods to get only in- or out- meta-edges of a commit
added methods to check timestamp inconsistency and build timestamp-limited subgraphs
fix : purge missing forks only when re-creating the forktree
fix : more consistent definition of getElement()