[log-api] Update api.
[log] DfsUtil: use IntStack.
[log] Drop unnecessary method from PermanentGraphLayout.
[log] Add IntTimestampGetter.
[log] Add PermanentCommitsInfo.
[log] Create new internal graph api.

Add GraphWithHiddenNodes as PrintedGraph and GraphWithCommitInfo.
[log] Remake PermanentCommitsInfo with CommitId.
[log] Remake PermanentGraphBuilder to PermanentLinearGraphBuilder with CommitId.
[log] Add draft of PermanentGraphImpl.
[log] PermanentGraphLayout -> GraphLayout.
[log] Move all from vcs.log.facade.utils -> vcs.log.graph.utils.
[log] graph.impl.visible.utils -> graph.impl.visible.adapters
[log] Fix update event in GraphWithHiddenNodesAsPrintedGraph.
[log] Add LinearGraphAsGraphWithHiddenNodes.
[log] Extract inner class.
[log] Remake GraphWithElementsInfoImpl to CollapsedGraphWithHiddenNodes.
[log] Add constructor.
[log] Some changes in CollapsedGraphWithHiddenNodes.
[log] Add FilterGraphWithHiddenNodes.
[log] Add draft files for PrintElementGenerator.