Broken out from bug 5870.
After making configuration changes in Web Admin it is easy to miss that you currently need to hit "Save".
There is no indication that a change has been done. For example, when removing an allowed shadower, the item is removed from the list visually, but you need to hit save to actually save the change.
* automatically save configuration right away (remove the need for a Save button)
* disable/enable save button if there have been changes
* warn that there are unsaved changes when closing the popup
Note that when changing profile order using the arrows on the Profile List page, that change is directly saved into configuration files.