Add default tableViewController editing / delete support

[orff]

By specifying a boolean in a new custom init method, it passes along a boolean into the FileListViewController which in turn set allowEditing on the tableView. Where I'm not sure things are going to be super smooth is re-parsing of the files and storage variables in the tableView's commit editing style delegate method. In a future version, this might need to be done on a background thread with an activity view display.

[marmelroy]

Hi @orff, thanks for this suggestion and apologies for the delay. I like this approach - will merge, perform a couple of changes and include in the next release.