Use custom adapater in import student tab [1/1]

[Problem]
1) The import student tab only lists student names and does not have an import button.
2) Fix issue where notifyDatasetChange() was causing a crash due to the underlying list being changed as the UI was being
    udpated.

[Solution]
1) Use custom adapater for import tab.
2) Put the updating of the UI all on the main thread to ensure exclusivity.