Closing the window while entering species should show a warning confirmation

[Adam Winer]

If you close the window while there's unsaved changes, you get a solid unsaved-changes-save-before-quitting? message.

But if you close the window while entering new sightings, no such luck, you just lose everything. Scythebill should use the same message it does if you click Cancel in that situation.

[Adam Winer]

Raising priority - hit a user (see Issue #521).

[scythebill]

Resolve #521: Closing the app in the middle of entering sightings loses all entered data with no warning and Resolve #179: Closing the window while entering species should show a warning confirmation and Resolve #105: Import menu item will cancel existing sighting entry without any alert

Two changes: - Navigating away from the Enter sightings page, while there's changes entered, always shows a warning - You can select Save in the middle of Enter sightings, and it'll save the currently entered state.

→ <<cset 4c94591edcee>>