adds test for adding users
add confirmation when trying to delete stage that has tasks and an error for when trying to create a stage that already exists
adds test  for removing users from tasks
shows warning when trying to delete a task
shows warning when closing an edit task tab, still need to keep track of edits
Merge branch 'multiselect_users' of github.com:slash-slash-no-comment-WPI-cs3733/wpi-suite into Add_remove_users_test

Conflicts:
	TaskManager/src/main/java/taskManager/view/ScrollList.java
checks if a task is edited and warns you when closing the edit task view, also warns you when viewing a requirement without selecting a requirement
updated the dialog boxes, stopped to warn user for creating tasks/view requirement since it should be a validation thing
merge dev-gradle into warnings
Drag to trash to delete
Adding a null check. The way we're doing this is already a little shady - still doesn't work well with the same names.
Make placeholder look more like a palceholder
don't store user objects with activites
fix for the duplicated stages
Merge branch 'fix-edit-task-with-new-task-open' into dev-gradle
Merge branch 'dev-gradle' of https://github.com/slash-slash-no-comment-WPI-cs3733/wpi-suite into warnings
deletes prototype dnd
Added comments
Merge remote-tracking branch 'origin/dev-gradle' into Add_remove_users_test
Merge branch 'dev-gradle' of github.com:slash-slash-no-comment-WPI-cs3733/wpi-suite into warnings