ISIS-872: trivial formatting changes to simpleapp classes.
ISIS-643: speculative fix to add a guard to an NPE if post delete processing.

... based, unfortunately, only on the supplied stacktrace and a bit of guesswork, since no reproducible case available.
ISIS-887: Removing references to isis modules from simpleapp and todoapp.

In addition:
- removed auth*_file config files
* removed ToDoItem's schedule* actions
* removed Quartz scheduler config from todoapp

also:
* removed empty ComponentFactoryRegistrarForToDoApp
* removed empty PageClassListForToDoApp
ISIS-872: removing references to components previously mothballed (in installer-registry.properties, and SystemConstants).
ISIS-884: to avoid possibility of XSS attachs, removing use of setEscapeModelStrings(false) anywhere that the content is dynamic (error messages etc).

Also, for JGrowl based messages, also explicitly calling Wicket's Strings.escapeHtml (the same underlying method that the default escaping does).