HydroModeler: Save prompt when editing model properties

Castronova[CodePlex]
When the user edits model properties and then clicks a different part of the application, they should be notified that they will lose their unsaved changes. Currently, the user is not notified that the changes they've made are discarded.

Start by locating the HydroModeler model-properties editor and the application navigation handlers, then reproduce editing a property and switching to another area. Trace where the edits are discarded; done means the user is warned before leaving with unsaved changes and can avoid losing them.

Written by the indexing model from the issue text.