Confirms and closes #34. Built simple use case for deletion on top of collections. Note that users may have to convert the point passed to the 'can delete' delegate method to a given deletion area to test. We _could_ consider allowing users to 'register' deletion areas with the coordinator so that they don't have to, but that is probably a bit restrictive as it assumes deleteion will occur on drop onto an 'area'. That might not be the case.