Popup: Fix default property typo

Was wondering about the property  `supressTitle` in the object returned by `af.ui.popup({...})` - because it also had no effect whatsoever when specified in config array. `suppressTitle` works though ;)

So i corrected the typo and also made sure the prototype default value is correctly overriden on creation (otherwise i would get back an object with property `suppressTitle: false` although i'd set it to `true` on creation)