Repeated calls to NotebookSession.listNotebookInfo()

[tdudgeon]

When opening a notebook there are lots of redundant calls to NotebookSession.listNotebookInfo() each resulting in a service call and database retrieval.
For instance, when first running the app when only 2 notebooks are present that are 9 repeated calls. See here: listNotebookInfo.txt

It should be possible to do this with only one call.

[tdudgeon]

Fixed: e586ad1
Would be good if someone can review this.